What really happens when you go over the 10MB limit on a free educational wiki?

I probably shouldn't admit to this but am currently about 13MB over the 10MB limit on my free educational wiki (v2.0). I have a warning saying I need to "upgrade immediately to ensure continued access to your files" but that's been there for some time now.
Can someone from PB Wiki tell me what will *really* happen - will I and the other wiki users lose access, if so when? I'm reluctant to spend scarce project budget upgrading if I don'T need to. Thanks