Somewhere down the line the OFT or similar are going to have to step in and standardise the method of charging. Its been done to the banks/finance industry/motor industry et al.
Advertised and headline prices should be based on the cost to get from A to B (and back), airport to airport, irrespective of payment type, industry standard hand and hold luggage allowanc. No other charges to complete the trip.
If any airline wants to reduce the price by offering luggage free options, money off by booking with a debit card and so forth, then let them do so at the end of the transaction. But of course that might just show some companies not to be quite as cheap against the opposition as they would like us to believe.