Know of a plant where they imposed a no make up rule partly to try and get control of the fake eyelashes. Employees really rebelled over no make up and wore the eyelashes anyway, their argument it wasn't makeup. Based on the product line the no make up was a bit of overkill, and it did get ugly between management and staff. Lost track of the person in the plant so don't know if it had a happy ending or not. 
It's not make-up. It's more like a tiny wig for your eyelids. Like a merkin, they still enhance the window to the soul, but higher up and smaller. My GMPs specifically say no false eyelashes / fingernails.
Because who wants to eat someone's nasty, gluey eyelash? No one.
You do what you do with every other employee who breaks every other rule - 1 documented "verbal", 1 write up, termination.
If I have to physically peel fake eyelashes off of someone because they are lying to my face, that's a write up. And if I have to do it twice? flip that noise, they're gone. I'm grateful that the people I work with aren't so disrespectful to me. If someone violated GMPs over and over again after I had asked them, nicely, a billion times, my head would explode.