It's much like how we maintain health insurance. I believe for my local you need one compensable day of work per week to maintain health insurance. Thats basically any workable punch or paid time off including sick days, option days, and FMLA. I'm not sure about vacation weeks. Our building has a half dozen on vacation this week. If they get paid out two weeks in advance, is there any verifiable hours showing up for this week?
They let off Quite a few guys today too. Most are scheduled off. They may have some issues. Everyone else was smart and used option days or personal days. Heck even calling in sick is better than unpaid time off. If you are ever unclear, use sick or option days near or around holidays.