6 Answers

Being Naughty,

I'm guessing crimes committed due to alcohol and drug use.

how long is your arm,,the reasons for people going to gaol is uncountable..ahhhh,i was going to give some insight into the inside of gaols,,but i might just leave it at ,,,,its a good place to stay out of...........however i new a bloke who once said...(you know when they put you inside, you fight with the screws,you fight with the crims,you fight with the family,and just when your so fired up you could just about kill anybody....you know what;;the dipsticks let you out,,,,,,nice talking guys,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,

Sometimes it's because they have collected too much money from Mayfair and Park Lane.

Social deviancy of one kind or another often results in punishment.  There are two ways to get the attention of an adult:  take away their money (fines, for example), or take away their time (incarceration). 
It's a "time out", often ineffective, but a break for the rest of us from the bozo.    

they commit crime