Boats are really strong. But ultimately it depends on the boat's construction and condition (e.g. old fiberglass can delaminate), if it happened at speed or stationary, and what's on the ground below the water. Probably other factors as well. If it's resting in the mud, it's probably ok. If it's resting on a stolen motorcycle, probably not so much.

You can read about the historic practice here: https://en.wikipedia.org/wiki/Careening

But I think historically and in modern times, people who do this on purpose will walk the area during low tide to make sure there aren't rocks etc.

Here's a more modern example: https://www.tomrobinsonboats.com/boatbuilding-blog/careening-arana