The only professional I can think of who's eligible for this years Masters who isn't playing at Sawgrass this week is Westwood. So no travel issue.
Players receive 12 tickets a day for family and friends plus a weekly badge for wife and children. You'd think non-competing invitees and spouses (past US and British Am champs, Walker Cup members), USGA and R&A committee members, heads of national golf associations like Oz and Canada, and limited guests of ANGC members would also still be in attendance. There are a ton of meetings that take place both on and off site among various golf associations during Masters week and for the week afterwards.
So I'd think you'd still have a couple thousand people on the grounds. And at that point you'd still need security, first aid, limited concessions, etc.
Obviously the Masters is far far down the list of things to be worried about right now. But it's gotta be a tough decision for the green coats. Especially since they are intimately aware of the financial impact there event has on the local economy for the week.
Michael