Don't think they have an issue  if you sign up/take bonuses but if you decide to close account at one casino they may close all your accounts at sister sites. This also means that in future you can't sign up at newly released casinos.  

A nice run playing Hacksaw slots 2 at a time. Moving on after it ended when I ran in to the fully dead combo of Donny Dough/Duel at Dawn.  

I've never had any issues with this. In fact, I find the casinos to encourage me to sign up and take bonuses with their related operators as well. But of course, if the whole picture eventually reveals that you only take bonuses, then they might not be so happy about it but exhausting welcome packages works just fine in my experience (mostly Dama/Hollycorn).

That's @Maiwen's field of expertise, the rest of us will never get to see a 1,000x on that one! 😅

I'm hunting Angel vs Sinner monster wins, eating my balance