Also, what the heck kind of place wouldn't let you use an FK at the office?
The Office is covering it's arse regarding the possible loss of a worker's own mouse at the workplace, which might lead to accusations and other uncomfortable workplace problems.
That is why most workplaces frown at you bringing in your own equipment in, due to theft and possible damage that might occur to that item. I remembered where I worked in a few places where knives were drawn due to stolen/missing - tools/equipment.
Theft is a major problem in any workplace.