Amount of posts needed to use private messages

[Fox Mc Cloud]

Is there a way or a mod to set that registered users need a certain amount of posts before they can use private messages so we can stop the spambots? I would like to do it without promotions.

[Dismounted]

What is wrong with promotions? They can do what you want. (And pretty much guarantees compatibility with upgrades.)

[Fox Mc Cloud]

Then the user won't see any error when they try to send a PM and I don't know how to disable PM's for certain users either.