Fed-ex charges are something I can't bill back with my employer so thus I won't spend a dime of my money doing something for work that I won't be reimbursed for.

Also, I work for a gov't agency that is prone to losing paper....on two occasions, I have had to go fishing for hotel receipts....i have to hand deliver it just to make sure it all gets there in one piece so im sure you can understand that using a simple snail mail or fed ex envelope just won't work for the ineptitude that is my employer.