You're wet/bleeding

[Dena Attar]

I have no idea how this relates to rules or maxims, but surely a very important point about the two particular situations you describe - being soaking wet indoors, bleeding noticeably - is
their abnormality. That means that the speaker who comments on them is responding to a choice - ignore the strangeness, which would make them feel weird themselves because they would be in a
false position, or acknowledge it, which would restore a sense of a normality and make everyone feel comfortable again. All that is needed to make things comfortable is the briefest
acknowledgement. It puts things right. Nobody is then pretending.

If you've ever been in a situation where there was something noticeably strange about you or another person but nobody mentioned it, it will be obvious how uncomfortable it  feels if the
observer says nothing and in effect  pretends they haven't noticed. This doesn't apply of course when a person's odd appearance is assumed to be a permanent state, in which case the rule is not
to mention it but act as if things are already normal.