By the way, back on topic, you can split off your reservation on-line - I've done it many times. You don't need to call.

It can be confusing to those who don't know how it all works. I don't know that it's a "bad" implementation. I think it's more the assumption that people travelling together don't want to be split up unless they say so. I can imagine a scenario in which one of the travelling party is upgraded when they preferred to sit with their companion and then the seat next to the companion is taken so they can't even downgrade after the fact. So Continental's system makes you state explicitly that you don't mind being separated from your companion instead of making the assumption that you do. I think it's six of one and half-dozen of the other.