It is probably true that we're not "organized" enough to run afoul of GNP regs. Not many people get permits in late May, so they'd figure out something was up pretty fast.
The larger issue is that Glacier terrain is bigger enough that a point to point course wouldn't offer more than one or two obvious routes. Though in late May and with proper care some bold folks with mountaineering skills could take some big shortcuts. One option for folks, especially those on vacation, would be to do a more mellow prologue over a couple days in Glacier, resupply at the Open start, and continue on. Might do that myself, in fact.
Though I'm leaning heavily towards the Bob for next year, I do intend to do a very snowy, high mountain course somewhere else, and soon. The Beartooth Plateau is a leading candidate, but I need more personal experience to evaluate the possibilities. I'd like a route where hikers, skiers, and snowshoers all have an roughly equal chance at being the most efficient answer.