Once I sent my passport in to Myanmar's Washington embassy for a visa. Two weeks later they called me on the phone and denied me because they didn't like my itinerary. When I got my passport back you could see where there had been a sticker that was then removed and probably some kind of stamp half over the missing sticker and half on the now empty page. That was covered with whiteout. I take it they placed the visa but then changed their mind. No one ever questioned it though and eventually an Indonesian immigration agent placed a full page sticker over it. If you ask some agents in some countries will place full page sticker visas over older expired ones as well and a few times I have had them place sticker visas over other countries stamps simply because they were to lazy to find an empty page. I have one page with 4 layers of Indonesian stickers. My take would be that it is 'wrong' for YOU to peel out a sticker, but if it so happened that some foreign immigration agent was the one who did it
then that is OK. I imagine it would be pretty difficult for a Canadian immigration official to verify if an unnamed Indonesian immigration agent did or did not peel out a visa last time you exited. YMMV depending on the countries involved.