Why abandon? Just resign.
It's malicious purposes, mainly.
And I'm sure sometimes people try to get an engines opinion, but don't get back In time.
I know sometimes people can lose their internet connections, but I've seen several times where my opponent is losing control (maybe a queen loss, pieces locked up, etc.) of their game and then the abort comes... Why not resign like a gentleman? Is this just a problem at lower level blitz play?