Just installed SEB 1.5 for MAC on a 64bit MacBook running Snow Leopard. Screenshots using command+shift+3 and command+shift+4 are NOT disabled. Perhaps I am missing a setting somewhere?
Blocking of system screenshots (cmd+shift+3 and +4) works only when running SEB on OS X 10.7 Lion. Due to an Apple bug in former versions of Mac OS X, it doesn't work when running SEB on Snow Leopard.
I changed the documentation to reflect this fact, sorry for the confusion caused.
It would be possible to block screenshots also on Snow Leopard, but this requires elevating user rights of SEB (or running a helper tool with root rights), which Apple doesn't accept in the Mac App Store and it will take a lot of work to implement. Most likely this will be included in a later version of SEB, because running a background helper tool with root rights will most likely also be necessary for new security features like process monitoring and killing not allowed processes. Please stay tuned, this should come in the next few months.
BUT we have to recommend to anybody doing e-assessement to design your exams in a way that it won't hurt you when the exam questions leak out. Nowadays there are micro cameras available which can easily be hidden for example inside clothing by the examinees or if every examinee remembers just one question, they can probably reconstruct your tests even without using such devices. I think it's naive to think that copies of exam questions would never leak out...
Nevertheless we will improve protection also from third party screen capture tools in the future.