Setting aside as to whether this will be fixed by 2.80 or 2.81, perhaps the thing to do would be, whenever it’s relevant, a warning “This operation would destroy old UVs.”, a list of all objects that would be affected this way, and three options:
“Cancel”, “Create new UVs and Proceed” and “Overwrite old UVs and Proceed”
(Maybe a slightly less wordy version could be found)
This way it would be entirely transparent either way.