They are probably wearing a hairshirt and don't want to make a fuss in keeping with today's Gospel. (Oh man, I'd better do penance for that smart aleck remark!)
Or they pray for their persecutors.
Friday penitential practices are always an interesting discussion topic for any group of Catholics.
Well, of course I assume that they are!
I never ask about it because I'm Anglican and I rightly don't get a vote. *eyes personal lunch of pea soup and rye bread* LOL!