If I'm not assuming people wake up in order to do a bad job, the more likely explanation to me is that
a) these instances are (seen as a percentage of dry land coverage) rather rare and
b) The test of being in water is simplified to `if height <= 0` instead of `if height <= 0 OR location.inside(some_super_complex_polygon_that_needs_to_be_looked_up_every_millisecond)`.
When you're flying over dry land, they already have to do a collision test to check if you have flown into terrain - so the solution would be to simply not check if you are above sea level when you are flying over land...
a) these instances are (seen as a percentage of dry land coverage) rather rare and
b) The test of being in water is simplified to `if height <= 0` instead of `if height <= 0 OR location.inside(some_super_complex_polygon_that_needs_to_be_looked_up_every_millisecond)`.
Done is better than perfect.