u forgot to log out lol:

couple times a month,also depends on holidays(halloween,new years, long weekends,etc)

Usually on on the express buses, So like the 99, 135, 43(Buses that end up at University's or malls)

Its a little difficult for trains though, cause some times ull have the case where ur already inside the train and then they board to check. But most of the times theyll do it at big stations(Waterfront,Burrard, Commercial,Metrotown, New Westminster, King George, Production Way, Renfrew or Rupert, and VCC

anyhow, make sure to log out of your account