In Canada, a ham may have up to four callsigns.
Hmmm....Not true, I know one Canadian ham who has five.
It's important to remember that the old American callsign assignment rules still apply in Canada. Here in VE land an operator must change his or her call when they move from one province from another. I was VA3AIT when I lived in Ontario; now I'm VA2AIT in Quebec (Why change the call?)
Again not true. I live in Ontario yet I still hold a valid VE7 callsign from British Columbia listed under my Ontario home address. I also hold a VE3 call.
Bill VE3CLQ & VE7CVQ