On plesk reloaded 7, when a client runs out of bandwidth, will it show bandwidth limit exceeded on their site? or will their site appear to be down?...

I just set mine to notify me in the admin panel when bandwidth is exceeded: I'm not sure if you can set it to disable the domain. (Haven't tried myself.)

(Notifications = an indicator next to the domain, + optional daily email)

Hmmm does anyone know what happens when someone goes over their limit? Does the site stop? Or does the site still work?

It still works.

In Windows server Plesk shows the correct bandwidth.

It will show you when it goes over and alert you if you have it setup. It will not shut down the site. This is something you would have to do.

I think thats gay, it should stop the site, and put up Bandwidth limit exceeded, please contact the administrator to resolve the problem.

What do you do when a client goes over their bandwidth, im assuming you charge them for overage charges?....

firstly keep an eye on their usage through out the month and let them know in advance that they may exceed their usage and will have to pay for it.

a user of mine was continually going over their usage by 30GB, so instead of charging them extra every month i got them to upgrade the package.