Of course any company has a right to pass along anything it wants to consumers, unless they are being deceptive. I think that if a company says it will give you 1,000 miles, or 5,000 miles, or 25,000 miles for signing up for their service, that it is an unfair trade practice not to disclose this to the customer. It matters not a whit that they have filed a tariff with the FCC authorizing them to pass along the tax. If MCI posted a tariff saying it was going to charge $10,000 per frequent traveler mile, does anyone think they could get away with it by saying they had filed with the FCC?? Of course not. The charge needs to be disclosed to the consumer at the time the consumer decides whether or not to purchase the telephone service.
Ever since I got into a dispute with Hertz this summer about their passing along the 7.5% tax on 30 Skymiles on a rental, with the amount of the tax being five cents, I have puzzled about WHY they would want to alienate customers in roder to make a nickel? Since then, when I have rented from Hertz, I have just asked for Marriott counter points since there is not federal tax on those (yet). Most of the time, I just rent from a competitor. They have already lost the nickel many times over. They don't care.