After booking a trip on United Airlines using frequent flier miles they noted that the costs for the first checked bag for each person was $90 each way (the actual flight will be on their partner, US Air, whose rate is usually $25).  

If they want to devalue frequent flier miles they should just raise the rates.  Tricking you this way is the opposite of good customer service.  

We’ll be carrying our luggage on, of course.

Continental was already slipping a little bit in the customer service area, but after the United merger it has been a free fall.  If you own their stock I’d sell it.