This. Its a very rare, uncommon issue. There are several hundred thousands of these phones in consumer hands, and think of all the retail stores like Best Buy, Verizon, Sprint, ATT stores that have them on display and hooked to that short cord. Customers drop and abuse those phones all day long in the store. If they cracked easily, they would be certainly breaking in the display stores and the retailers would be making a big issue of it with LG.
Personally, i've dropped mine 4 times on my hardwood floor and never cracked. A lay in down on my glass top desk probably 50 times a day against the camera glass, over and over. And i put the phone in my back pocket when out, and even sitting on it for a week while gambling in vegas (cant keep phone out while gambling).
There hopefully will be a replacement kit soon on ebay or amazon, just like you need for any part on a phone. Samsung has sold THOUSANDS of replacement camera lenses on ebay for just the S7 alone.
One thing I would avoid, with any camera phone, is over using the camera flash - particularly using it for a flashlight for a long time. Heating up glass is the worst thing for any type of glass and can cause it to crack. It causes one side to expand, and when these things are installed airtight, there is no where for it to expand. Thus the crack.