I've bought Zagg shield's before and paid the extra fee to have it installed at best buy. The first time I did this was a couple of years ago, at a Best Buy in Lakeview, Chicago for my iPad mini, paid the fee for installation and was told if there were any problems to return it and they would replace it if necessary. Within a week, it started to peal around the edges so, I returned to the store and they replaced it with another shield which they also installed.
Last year, I had a similar experience at the Pensacola, FL best buy store. Same issue, Zagg shield I had purchased and paid for installation on my iPhone 6 Plus had cracked about a week and a half after I'd purchased it. As instructed, I went back to the store and they replaced it it with a new one, same experience that I'de had at the Best Buy in Chicago.
A couple of weeks ago, I bought a Zagg shield for my iphone 7 Plus and paid the extra fee to have it put on my phone. About a week and a half later, it was cracked, so I went back with my receipt like I had on two prior occasions at two different locations expecting the same experience, but that didn't happen.
Initially I was told I would have to submit a claim to Zagg, send the broken shield to Zagg, wait for them to send a replacement, then take that one to to Best Buy and they would install it. When I tried to explain that my two previous experiences with this issue were differently, I was told that wasn't their procedure, they seemed to question if I was being truthful about getting the other two replaced, and they said they would lose money on it. I suggested they keep the broken one but was told Zagg would just throw it away. After some discussion, a manager approved a replacement shield and installation for me, though it was again mentioned that they were losing money on it, which made me feel uncomfortable and embarrassed. I didn't intend for them to lose money on anything, and was simply doing what I had been told to do at the time of purchase at two different Best Buy's including that same store.
The shield itself, obviously is't perfect. Though each one of them had been expertly installed all 6 times. It doesn't sit flush with display, of either phone or iPad so there is a gap all the way around that collects dirt and dust.(see attached pics)