Google might keep your Pixel during a repair if you're caught using non-OEM part (androidpolice.com)

Straight up theft . Wow, even Apple's Terms aren't shitty enough to state that (although they'll charge you a fee). https://www.apple.com/legal/sales-support/terms/repair/gener...

This sounds like a clear violation of the Magnuson Moss Warranty Act, which would make it illegal in the us.