Re: IT can be a pain in the arse too
Your housemate (and presumably yourself) haven't heard of usb pen drives then? Certainly quicker than email - and if she has the Macbook Pro with her at work, why doesn't she just load up the files she needs before she leaves the office? It's what PC users tend to do (but only if company policy allows).
Is Citrix the remote client required by her company to be used for PC remote workers? If so, she is being treated no differently or 'lazily' by IT. Has the company's management implemented remote working policies that dictate what the IT department is allowed to provide (that is usually the case)? If so how is that translated into 'laziness from IT departments'? If MS Remote Desktop Client is the company's required remote access client, it is also available (FREE) for Macs, so why isn't she using that?
A Mac is just a pretty PC using a closed form of UNIX/LINUX as an OS. I don't believe that a professional IT department knows nothing about them. Macs are no different to any other PCs in function (only in the minds of the self-appointed 'elite' that use them) and there is nothing that can be done on them which can't be done on any other form of PC just as effectively and usually cheaper.
The budgets available to IT departments are usually inadequate for the tasks and results that senior management expect, and more often than not, spending of any budget must be approved by a non-IT literate senior manager - usually the CFO. It is never as black and white as you paint it.
From an HR perspective, why hasn't anyone questioned why she wants to work in her 'holidays, etc'? Such times are given for resting and taking time out free from work, and are necessary to one's well-being.