Why is the person on the other side relevant to the purchaser of the seat and the empty seat? I'd say the purchaser gets dibs on the underseat space. Other'n that, both pax will enjoy the fact that the empty seat is there.

I've never heard of this kind of program. I'm surprised that it exists...figure a typical R/T in business class is going to run $5-6k R/T to Europe or Asia after all of the typical corp discounts. (Yes, Orbitz shows $9-10k but the companies that actually buy these tickets don't pay anywhere near that.) Figure a coach trip is going to run $1500 or so...obviously more variance there. So 2 seats plus $1500 round trip...doesn't seem like the company is saving much money.

Sure, I'd do it, but I've flown a lot (including a bunch of international coach) for business and never seen the policy or met anyone else who had it.