Of course, it's possible.
But I just wonder why do you think it's an ethical/moral issue?
It's just a matter of losing $$$.
I know someone in a situation (which I may be in soon) where they have applied to a second class and a first class school. The second class school is something like Schulich or Simon, but they also put in a chance application to a top tier.
If the person gets accepted into the top tier program, is it moral and possible for them to drop out of one program and join another- even if they have been in the lower grade program for a few weeks?
Does anyone have any info or experience on this?