I think I am going to go inside of someone's parking garage so I can smoke.
Are there other people who are smoking in there as well?
I will, they all do it. Everybody else is doing it.
You should respect the law even if other people are breaking the law. You could get a ticket if you get caught.
Fine.
It would stink if you were caught smoking weed and you also got into trouble for being in a private property. You are better off just smoking on your own property so there is less risk, or just not smoking at all.