So I've been playing some @ FCP, trying to clear my bonus and all.

The problem is, there aren't any games so obv. I have to be the one who starts them up if I want to clear this bonus. There are some who'll sit down with me, play me HU for 5 mins, and as soon as they're up $50+, they get up and leave.

I'm not a fan of doing the same thing back to them.

But

next time the same person sits down to play against me, should I just refuse to play him or suck it up and hope I get him stuck over $50 so he sits n stays?

Hit and runs are meaningless.

It's all one big session.

So he takes you for $50 now, next time you take him for $75, or you take the next guy for $75. Big deal. Continue to play winning poker. It doesn't matter if it's against the same villain or not.