I think he could do it, he's a smart and underhanded. The owners wouldn't stop it, imo, as they'd receive their share of the relocation fee.
Personally, I see the league expanding to 36 teams over the next decade. Seattle and Houston are both highly attractive markets, and should Melnyk move the league could easily find an ownership group here to fill that shiny new arena downtown.
So twice the money to the owners and the outcomes are the same either way, but logistically if QC wanted a team back, it's easier to relocate than expand and Ottawa is the more attractive expansion market.
I pray it doesn't happen, but I could see it.