Apple Watch Series 3 Shattered for no reason

I laid watch on picnic table while swimming. Checked a message at 2:37, laid watch back down. When I got out at 3:10, watch was cracked around edges and sound had been enabled. I always keep it on vibrate. Apple says it’s not under warranty and would charge $200+ to fix it. I thought maybe it got too hot, but it’s only 80 something here today and the watch was only exposed for about an hour. They want me to take it to an apple store, but I feel like they are just going to want me to pay also since that’s what the lady online said they wanted. Happened to anyone else?