Sure, but when 'big' is $100M, I wouldn't really call that amateur.
If they'd done $1M nobody would have heard about it, nobody would bother investigating too thoroughly, and they'd just shrug and move on.
The "pro" thing to do is to take your $1M and walk away even though you know there's more money at that tap.
There's a lot of casino cheats that talk about their craft. The good ones work extra hard to give the constant illusion of losing money which helps them win a little bit more without drawing too much attention. There's a whole art to knowing where the line is and not crossing it, flying completely under the radar.
That's what professionals do.