Drawer deals are technically against the rules. It was a big subject at GM meetings, so a deal with Oshie being "all but done" now but not made official until after the expansion draft could cost the Caps a sizable fine and a first-round pick.
For every GM and owner out there that might be willing to play fast and loose with expansion rules, there's other GMs and owners that are sticklers. So trying to get deals like that by the league's smell test will be risky.
I don't think signing Oshie is really a concern anyway. We can protect 7 forwards. Ovechkin, Backstrom, Oshie, MoJo, Kuznetsov, Burakovsky, Wilson. Who are you sweating losing? Vrana isn't eligible and they'd be doing us a favor taking Eller. Williams and Winnik are gone.
I'd miss Beagle, but let's be real. If Vegas doesn't take Grubauer or Schmidt, they're nucking futs. We don't have to protect Beagle. Protecting Oshie isn't a problem.