The nicknames are so someone looking for you can't just come in the poolroom and sneak up on you, like the cops.
The nickname must be given by someone else, and must pretty accurately sum up your personna.
Mine is "Hey, Pool Dude".
I walked out of an all night pool room at about 3 Am one morning and there was a full blown blizzard going on.
This obviously drunk and obnoxious girl sees me with my pool case from half way across the parking lot and hollers , "Hey Pool Dude", in just about as sleazy a voice as I have ever heard ,"can I catch a ride home".
Against all my intuition I asked which way she was going, she was headed in the opposite direction, so I said,come in the pool room and I will call you a cab and pay for it , I am going the other way.
She says ok and I start walking back in the pool room, I opened the door thinking she must be right behind me and I look back and she is gone.
Then I thought she might have fallen down so I looked behind and around all the cars in the parking lot.
I still wonder how she disappeared like that, we could have made a fortune as a magic act.