Is there any type of lens cap that will stop itself short of destroying the lens if you accidentally put it on backwards... ?

Although some old caps are made of metal and may damage the glass or filter threads if not used carefully, most modern lens caps are made of plastic and will not harm the lens if accidentally put on backwards, unless they have been dropped on the beach. (Sand will scratch glass.)

Is it possible you just made a light mark on the coating that can be wiped away?

You can try gluing half a ping pong ball to the front of the lens cap. You can also purchase caps that have already had a similar procedure performed. Presumably, these caps have other functions that you might find useful.

Some other options:

• Pay attention to what you're doing.

• Use transparent lens caps that are semi-permanently affixed to your lenses. These are often referred to as "UV filters", but what they really filter out are oil, dust, and scratches. (High-quality "multi-coated" filters should have minimal effect on image quality.)

• Use lens hoods instead of caps. These function similarly to car bumpers.

• Use pre-distressed lenses and cameras. An extra scratch or two just adds "character". (See Fuji X Weekly: Distressing a Camera.)

  

Or should I just never touch the camera?

What does your wife say?