This is a very common practice these days. I too check my emails, fill timesheets from my personal rig but apart from purely read-only mode I cannot download, upload or even copy text across due to restriction. I was also pissed off but been into compliance I can certainly understand the demerits of allowing all these as data exchange/selling outside org. to 3rd parties etc. have significantly costed companies crores of losses esp. their clients exiting their biz/contracts prematurely!
You shouldn't dare to fiddle with anything else one trigger alert and you are in the red zone and then be ready for logical explanations for your act and face severe consequences!
