I'm a Mbnet user aswell, and never had issues with it on gog.
I did have with steam one time during a sale, when i did multiple purchases, had my account purchases suspended and had to go trough a support ticket and even steam reinstal to solve it. Since i havent used steam for purchases in a while and probably wont ever again its a non issue.
My bank € settings for mbnet allow to set the daily max use for the cards, and the card creation itself allow to set the limit for that card, and i havent maxed it ever and its not likely i will ever need to considering the average gog prices.

I'm aware of that thank you but it's just that until now I've been using "traditional" mbnet cards that expire after only 1 use (and one multi-use card limited to €10). But since the purchases kept pilling up I made a few.

I'll make a large one like that then. While GOG doesn't store credit card info I'll prefer avoiding trouble altogether.

The only problem with mbnet multiuse cards is you need to note down the 3 digit code since that isnt stored on the card info (edited my first post since i misunderstood what you were asking about).

http://www.mywirecard.com/en/

Partly from memory:
German bank.
A debit account with a virtual (or real if you want) creditcard linked to it.
Limited to €2000 per year or per 12 month period, not sure.
Transfering funds cost €1 per transfer, no matter the amount.
Can be linked to a paypal account.

It doesn't actually expire from 1 use, since the minimum amount is 5€ i use it multiple times in bundles, 1€ here, 2€ there, etc, the limit is actually 1 month and only that. (ignore this non portuguese speaking gog: Repara que lá diz "Indicado para 1 compra apenas" no sentido de recomendado, é uma sugestão).

I also never had problems with gog, just with Steam and Paypall where i had to explain what mbnet was. Btw, how did you limit your multi use card for 10€ only? I know that you can go to the atm and change the daily amount that you can spend, is that what you're talking about?

The virtual cards in the US have a number, security code and our own names on them, they're indistinguishable from regular credit cards.

Is that not the case with the virtual card you're using?

Yes, it's the same as a credit card, you decide the amount you want to put on a card and the site will generate a virtual card (with the information that you mentioned) for you to use with the money from your account but there are two settings, one is the quick-to-use with one month only and the other gives you the option to choose how long you want the card to last.

Thing is, in this case, he has a limit of 10€ for the second option (i don't know how) and he thought the first option only let him use once (as a disposable cc, after one use is gone) so the problem would be if gog would block his account for adding/using multiple cards on gog (as a safety mesure against stolen cards).

And, well, even if he has the same name in every card there's still a possibility of getting the account locked, that was what happened with Paypall and Steam.

The maximum limit is set on the website just as you are creating the card. My monthly (set through the ATM) is much higher.
I CAN make a card with much higher limit, there appears to be some confusion on that, and I'm probably going to do that next. The reason I usually make low limit cards is because I don't usually make many purchases with mbnet at all, only very occasionally (just recently joined gog) and because of security reasons (in case the info got stolen somehow, the theif wouldn't be able to steal much money if any at all).

The reason I made the thread was to ask if I could get in trouble for essentially using many different credit cards which could be considered suspicious behavior by those not familiar with the service.

I've used virtual cards many times on GOG (tho not lately) and haven't had any problems.

Hopefully your experience would be similar.

I've used virtual cards on nearly all my purchases from GOG, and with over 500 games on my account and a few dozen gifts given, quite a few purchases have been made.

Not living in Portugal, I obviously don't use the Portuguese service, but I instead use my bank's own service. Their virtual cards are limited to however many months I choose and whatever amount I choose, PLUS they're limited to the first "terminal" they're used with, which causes problems with some stores (Amazon, for example) that uses one "terminal" for checking the card (reserving a small amount that later gets unreserved and never actually charged) and another for the actual charge, luckily, GOG doesn't do such a check.

I've only had a problem once regarding this, a couple years ago - I sent GOG a support request then and (as implied) haven't had any problem since.

I can recommend Entropay.
There are some bad user experiences about the service on the net, but personally I am a very satisfied user.

You can get a virtual Visa in few seconds, and the best thing is, you can have the same virtual card and same card number and just load money to it from time to time. Like PayPal balance.

It really helped me a lot when my credit card payments got denied when trying to use my card with British Kickstarter. The weird thing is, I was able to use my card with "normal" Kickstarter (Amazon payments), and I was also able to use that card to transfer money to Entropay virtual Visa. But all attempts on British based Kickstarter projects failed.

Virtual Visa helped me out, and even though I lost a few cents, it was still a good choice. A virtual credit card from a local bank would have had an opening fee of 10€, so it's not really even an option... Don't see how it could cause any trouble.
If you can use your virtual card to pay, GOG is happy to get the money, and that's the end of it.

I haven't ever used virtual cards on GOG though, so can't speak from experience here. But as credit card information is not used to identify anything, there shouldn't be any issues even in theory, other than your credit card, virtual or real, not being accepted for some reason.