I've been the victim of this and the doer but i must say it is truly a pathetic, cowardly thing. Just shows how little care you/they have/had for the relationship. Never again.
My ex of a little under 2 years, did this to me, and tbh I felt disrespected.
True enough, I was gonna end the relationship myself, but I was waiting to do so in person.
Either way, I sent a text back agreeing and that surprised him a little.