they will watch you, but not too closely. generally you will call once a month, usually between the first and tenth of the month, and the PO will tell you that you have 12 hours to come in. i was never called randomly to come in, but it is possable.

before i went on probation i quit for a month and bought a few home tests. after experimenting i found that i could smoke once a week and be clean in 2-3 days, so that's what i did. i just made shure to be clean for about a week before the test to be safe.

really it's not worth going to jail over smoking some pot. imo, showing that pot is not addictive, only habbit forming, proves that smoking pot is not as 'bad' as people say.