That would mean connecting to each of those users computers, wasting valuable bandwith etc... There is no real point to it, you may aswell ping them, and if they complain just tell them you're testing something and explain to them... you can even make a quick text:
name this as: /test
code:
/ping
#1#sorry
#1#Just testing to see if you have messenger plus!
#1#if not then why not download it from here: www.msgplus.net 
.
just advance it from there onwards...
I'm pretty sure that there used to be a feature where you used to hover over their names and a little circular plus! logo appeared
.
