Haha, really? I thought it was MUCH harsher.
Yes.. infact, all rules are rule 1. there is only 1 rule. that is DONT GET CAUGHT!
I have not experienced this. I can tell you the legalities though.
Fines are a maximum of 25 penatly units ($100 per unit). That is for defacing ANY type of public transport in anyway. I'd expect the law to prosecute you further however, and of course painting trains would give you a much higher cost of fines (IF YOU WERE CAUGHT, in which case u shouldnt be, because ur smart enough i hope)
For buildings im not sure, but depending on age (minors), they MAY give u a slap on the wrist and community services with small fines.
It really depends what you do, and how much of it.
Hope this helps slightly.