Usually, it is enough that you played Blackjack. By far, most claims by casinos of "bonus abuse" are where players have played Blackjack and won. If you had played other games, the likelihood of being accused of this are much smaller. 888 seem to have a funny view about Neteller, preferring instead credit card deposits - they told me this when I asked about it, and decided not to play anymore as I have credit cards in UK pounds, which makes it uneconomic to deposit, even more so than with Neteller.
888 were involved a while ago with "black hat" marketing tactics, and do not appear in the accredited list here. Although based in Gibraltar, their behaviour is closer to that expected of an
RTG Costa Rican operator. They gain many customers through direct advertising, so are able to live with the loss of custom from experienced players. The only recourse is a complaint to Gibraltar, but this seems unlikely to get beyond going on file.