thats actually a really smart solution 

i know this is abit off topic, but i can't help helping other ppl to outsmart big corps...especially in this part of the forum...

try this:
when u only have 2 ppl (coz easier) try to select a random seat for one person (without paying)..make sure the seat randomly selected has an unoccupied seat beside it....choose that seat without paying...
in quick succession, for the other person....faster go and buy the seat next to the randomly selected person....voila!! u just need to pay for one seat...

(or if u understand, use 2 diff type of browsers will have 2 session, use one to lock the seat first, just like u lock the cinema seat, and buy almost at the same time)

was gonna try this out in my trip next week as we have 2 different bookings, but i was waiting till weekends, but then again my gf said it's ok to sit separately 

i think this will work better if u check in early..do try like other forummers said, coz all these while, same booking usually sit together...

Are u talking about AGODA hotel booking?

Not a surprise to me for this promotion as TGV just changed their terminal from CBB to MBB.