Definition of hairline crack.
I bought an Ipad Pro 11.5 six months ago and have treated it with the utmost care. One morning, after the ipad had been in my bag all night, I opened it up and found a crack going from the mid-left of the screen to the bottom right. There were no splits from the crack, and no sign of physical damage. I took the ipad to a retail store near my house, and the apple technician immediatly said it was a hairline crack, and is under the 1 year limited warranty. To my dispair, we also found out that I bought my ipad from a different retailer. Long story short- the other reatailer said it wasn't a hairline crack, and haven't given me any proof of that claim, and I suspect they said that only to shake off paying for my new ipad through the warranty.
Bottom line, what I would like to know is what is the official definition of a hairline crack, and how does an apple technician define what is and what is not a hairline crack.
Thank you
iPad Pro, iPadOS 14