All 30 teams will have someone picked by Vegas. Some of those players will end up as McPhee's trade fodder or in Vegas' AHL affiliate once the season starts.
Next off, think your example through to completion. Instead of just losing Orlov, they end up losing Orlov AND Schmidt, and get nothing but a 2nd round pick in return. That's awful. If it's a "buyer's market," you're not going to get good value on the assets you're peddling away. This is doubly true when you consider that most other teams aren't going to have the space to protect additional defensemen.
There's going to be a few notable exceptions where teams struggle to move a NMC player in order to free up a protection slot they can use on someone else (say the Rangers trying to peddle Girardi or Staal, for instance). But otherwise teams are going to realize that they're going to lose someone they want to keep, and instead of playing into a "buyer's market" where they end up losing two players, they'll settle for losing one.
[An aside regarding Caps specifics in your post]
There are numerous other ways they can avoid the scenario you described. If they aren't liking the direction of Alzner's contract negotiations, they can expose him. Depending on what happens in the goaltender market, there's a real chance that Grubauer ends up as one of the three more attractive exposed goalies (unless Pittsburgh fails to move Fleury, and has to expose Murray as a result or McPhee negotiates a deal with UFA Bishop). Both of those could prevent an Orlov selection without resorting to trading Orlov.
Additionally, I disagree regarding your assessment of Schmidt being a player not worth caring about.
(Both of them.)
