Explicit fall-through in switch statements?

[Frédéric Delanoy]

For every wine version, static checkers (like coverity) detect cases
where a switch case automatically falls-through to the next case.

Shouldn't be there a rule that such cases are always marked with a
"fall-through comment"?
With the possible exception of case with no statement? like 'case FOO:
case BAR: do_something();...'?

This would probably help IMHO, especially when people refactor old code.

Frédéric