I'm not sure how safe Hamilton is. I know in Toronto there are a lot of bike thefts. Here are some tips to keep your bike secure, might be a little much for hamilton though:
Use a chain lock AND a U-lock.
Always lock the bikes so the key hole is facing down, that way if anyone has to pick a lock they have to pick it upside down or lying on their backs.
I don't remember which, but use one lock to lock the back wheel to the frame and a chain lock to lock the back wheel to the frame to the bike rack. So I think you use the chain lock for all three and the u-lock for the bike to the frame.
If you can take the seat with you. I'll give the bike thief a hard time to get the bike to where he wants to go
If you can file down some numbers and letters onto the bike and write it down somewhere. This is incase your bike is stolen and the police recover it. Have you heard about the thousands of bikes the police have retrieved in Toronto?