Messenger Service Risks?

Dear Sages,

I want to enable the messenger service on the workstations on my network so that my users can receive notifications when they print (or, more specifically, when they fail to print because they’ve used up their print quota — thank you PaperCut NG), but I’ve heard there are some security risks when you enable the messenger service.

Is this true? Do most of you live without NET SEND?

Thanks for any advice,
Lev in Brooklyn