Thanks for the replies. To clarify, I would rather know what the protocol is and how it affects me than just show up and find out. I'm not trying to avoid screening, but it sounds like it's unlikely anyone's going to ask and I have found no information about how they're actually identifying whether someone's been in Uganda in the previous 21 days. I'll be clearing customs and immigration at YYZ, I'm guessing there will be no questions to anyone about previous travel.