I usually leave a couple bucks for free meal. 2 loonies on the pillow for the maid too ( greenbacks in the US). Also the RoomService people get the short end of the stick as people assume that the Service Charge $2-3 on the check is a tip. It is not.
When I'm not sure, I ask. Staff are always great at telling me when it's included of not.
I tip normal for OK service (15-20%), but give me poor service and watch out. Can you say Zero. I think that's a fair deal.
I'm happy to part with a couple bucks for an enjoyable experience. If others want to blow the issue out of proportion they can.
What's a couple of dollars, tho .....