I’ve noticed that Continental.com’s search engine consistently errors when searching by multiple passengers. For example, today I booked three tickets separately at $540.58 each. When I had searched by “3” passengers, it had give me a price of $1798.44, or $599.48 per passenger. One would assume this is because a lower fare bucket has less than three tickets – but the three tickets I booked separately each had the same itinerary. This isn’t the first time this has happened. So if you’re looking to book for more than one passenger, you may wish to purchase each ticket separately (do a trial by placing them on hold first).

I'm not so sure that it is an error but just a way for CO to grab a few extra dollars from anybody who gets a bit careless when booking. I too have noticed this problem from time to time and handle it by booking each ticket individually. It is very annoying and does not seem to have anything to do with fare class availability, showing up the same on all the booking engines, not only continental.com.

What's the inventory locking behavior of the system and what is the activity level?

I'm wondering whether it could be the case that there is enough "activity" in the system to cause it to have only two spots left in inventory - for example:
1. The Q inventory has three seats available.
2. Someone has one spot in the Q inventory locked up in a transaction. This must be pretty common.
3. Your query for three seats only finds two seats available in Q and has to bump one passenger up to V.
4. You say, hmm and do the thing as three separate transactions. By the time you get around to the third, the person in #2 has decided to cancel their purchase and the inventory is available.

Does everyone in a party have to travel at the same fare basis on all legs?

It's the same fare basis, and there's still plenty of seats left in the fare class. I can repeat the situation - I'm guessing it's either a bug or intentional.

That's Gordo-the-Liar's "Excsssive Passengers" fee. He figures if there are three of you, one in the party is more likely to take more peanuts or napkins than you're entitled to and thus the extra fee.

This behavior is pretty interesting, given that the system is deterministic unless fares change.

Did you notice whether the fare classification was the same on each segment? Just trying to pin down whether the bug is in the fare selection or inventory pull.

On reflection, I'm not sure what I could do with the information.