She loves me she loves me not!

Every speaker is different. The Spendors that I've owned were better with grills on, but almost all others I've had were better with grills off. Store them in your closet if not being uses. The garage is no place for them. 

I remove them when listening.

I replace them when I'm finished.

Why are you moving your speakers around in the garage? Put them in their place in the listening room and leave them there.

If you feel the speakers are unsafe with you near them, leave the grills on except when you’re’ listening.

For all the money you spend to buy the KEF Reference series speakers, they don’t even come with grills.

I tried my Revels grills on/off when I first purchased them. The grills had a noticeable detrimental effect on the sound. Luckily the baffles have the same finish as the rest of the cabinets. I also know where the grills are, on the top shelf, in the back of the garage, with all of my saved component cartons.