Every account has a value, and if you are ahead or running close to even, you might be told no. Some casinos will notice and drop you off a chip after a bad run.
It doesn't hurt to ask ever, as long as you don't get upset if you are told they can't offer you anything at this time.
I almost always use live chat, but if some places live chat have little authority, you might be better off emailing support at those places.
Slot players generally get more, as we have a higher house edge, so there's a little room for the casino to toss us something after a bad run.
I've had a little kindness a couple of times when my account wasn't really in a position to offer a free chip, but they found a little something when I was having a deposit issue or such.
Also, a bump of a $1 or two to redeem loyalty points is a very modest request from a loyal player.