@carollu
I was banned from my gym for bringing in a guest after hours
Bro, that's called theft and trespassing. It's not tolerated because, well duh, it's illegal.
You should be thankful the owner didn't call the cops while you came in the next day or whenever and call in the cops to have you arrested. I assume this place has cameras around and could easily have pressed charges with said evidence, along with you workout pal. I dont see why youre not thankful that didnt happen. Next time read the contract and exercise common sense, you wouldnt want someone free loading and trespassing if you put in your own money to start a gym would you?
Edit: I would personally would have called the cops on you. Also your workout pal probably didn't sign a waiver which means he's a liability and set the owner for a potential lawsuit.
People are also using the showers, and toilets etc
There was a gym I knew about where all the members had access code to a 24/7 and were giving the code away. He expressed his concerns online and called it theft. He later implemented a key system to reduce said crimes.