can the discuss forum user choose whether to accept conversations from other users?

Hi!

I was wondering if users can decide whether or not to turn on 'conversations' function.

I know that, as an admin, I can enable or disable conversation functionality. But I was wondering if -- after i enable the conversation function -- the user can choose to personally, from the front end, enable or disable the ability to receive messages.

I am asking because I am having some problems in my forum. My users love the PM system: it works perfectly, and the configuration/UI is so neat. And so they love it, but the problem is junk messages from spammers -- but not bots, from other users.

I cannot monitor every conversation and blocking individual users takes too much time. IF I can allow users to enable or disable chat function then that will solve this problem.

What do you think?

Thank you for your support,
Ben