Is it time to start calling out bad cyclists?

Another thing I was going to say (but has probably been mentioned a million times already, so sorry about that) but what is it about people putting red lights on the front of their bikes?

Last night I saw two people on my cycle home with no light on the rear but a red light on the front.

This^ is proper weird.

I was cycling along a narrow road, on an evening roadie spin, a couple nights ago. When I saw what I thought was a cyclist going in the same direction, ahead. For a minute or two, I thought I most have been going at an truly amazing pace, to catch them so rapidly.