On frwiki, I use the forceeditsummary option (Preferences/Editing/Editor), but I sometimes I just ignore the warning, for example in case of a revert when I think it is self-explaining.
While doing this edit (the page was subject to Abusefilter 36) I got locked in a endless loop of warnings: each time I clicked the save button to ignore one of those warnings, the other one was preventing me from effectively saving the page.
(note: I was able to finally save the page because I know that adding a whitespace to the summary suppresses the forceeditsummary warning without changing the final value, but this is not something a user should be supposed to know)