I had an interesting period of time today with a student who could/would not see the superfluousness of 'met up with' over 'met'.
Just out of interest, do you see a difference between the two?
I was trying to point out that 'met' is perfectly acceptable. and 'met up with' is two words too many.
I didn't want to start a fight, but to be honest your pedantry ill-serves your students. I presume you tell them to say, "It is I", instead of "it's me".
Whilst both are acceptable, there is a slight difference - met up with is more formal as in a date, met is more informal - i.e. "I met up with sibton, as we agreed, at 10pm on AM." versus, "I happened to be in AB town and met Sibton in the street."
'Met' could infer that it was the first time you had met the person and would need qualifying by a statement such as 'I met X who I've known for years' whereas 'met up with' infers that it is someone you already knew.