I have to disagree on the voucher issue... the "oh, but your reservation was cancelled, but we didn't tell you, and we have physical possession of your voucher" would definitely fall into the "what's the catch" category when the time came for me to check in to my flight.
Being very honest - this subject was brought up by me because I have been running into a lot of salespeople lately who seem to believe it is OK to let the customer believe everything is fine even when it is not. Now, I have been running into this more with other things lately, but I am interested in seeing how it plays out in travel.
I just wrote an article about cruise line "Choice Air" type programs where they lead you to believe they will take care of your costs if you miss the ship because your flight is cancelled. They will make phone calls for you and try to get you rebooked, but any ancillary costs are your responsibility.
The unrevealed tax & fees are not as bad as the luggage costs with the airlines - the latter are never figured into the base price they show you when booking the ticket.
With a cruise you do see the taxes & fees before you make the final purchase - but not until that point. It does make a big difference, say if you thinking about either Mexico or Alaska. Alaska taxes & fees are usually much higher.