What's the incentive for Las Vegas to do that though? The NHL made the rules so that good players wind up on their roster and the league is going to "advise" management on who they should hire as GM. They aren't going to suggest a GM who would rather have magic beans than de Haan, it's everyone's interest that Vegas be competitive right away.
What kind of package would you give up from the Islanders roster in exchange for de Haan or Pulock? I doubt we'll see many trades of the "please don't take good player x" variety because a quality NHL player is generally preferable to whatever quantity offer you put together. We might see a team bribe Vegas if they only have scrubs and negative value contracts exposed to take cap off their books, but it's naive to think a team can wiggle out of losing a good player they can't protect.
Las Vegas will be in a good position to negotiate because they only need 12 forwards, 6 dmen and 2 goalies. Suppose there is 5 quality goalies available, you obviously wont take all 5. So if a GM comes up and says; listen, if you're not picking this goalie, and instead you're picking our scrub forward, we'll give you a 2nd in 2017 and a 3rd in 2018.
As the GM of Las Vegas you take this deal because there are 4 other goalies you can take, so you'll gladly take the free picks.
Those back-door deals happened before and they will happen again. It's a win-win situation. The existing team keeps their asset and the new team gets draft picks AND still picks good players.