what I find tough about the Jays is not knowing when, or more importantly WHERE, they will respond and put the letter back in the mail.
As we know some players take time to respond... you can send to them c/o spring training and they can sometimes respond mid-season, or vice versa.... or sometimes in the off-season, and sometimes years later...
so if you send to the Jays with Canadian postage on the SASE, but the player only responds when he gets home (most likely the USA) in the off-season or the following year at spring training.... it may not get to you because it doesn't have American postage.... and same thing goes if you send to the Jays Spring Training Camp and they respond from Toronto, the American postage you included on the SASE probably won't work from here in Canada.
I did get lucky once with the postage thing tho. I got a return post-marked from Florida despite having Canadian postage on the SASE.
I have had returns c/o the Jays (both c/o T.O. and Spring) over the last few years... but many were after a few tries and I'm sure some got lost in the mail because of the postage problem.