Our policy is pretty wide open, as a Fortune 500 company. Reasonable expenses, reasonable travel times, etc. - all at the travelers discretion. No business class, period, unless you are a company officer. Alcohol, sodas, bottled water from the corner store, visas, etc., are all reimbursable.

The only weird one we have is no renting a car or driving allowed after a transatlantic or transpacific flight. We're required to use a car service, taxis, or mass transit. I'm fine with that, since I don't want to make the ~100 mile drive to our office in England after arriving at LHR.