Have had success with this in the past in JNB and SIN, but it was a struggle - especially in JNB ... They really are not keen on doing this ... had to be done with a hand written tag and warned that it might not work .. but it did turn up on the carousel in Doha.

I would consider brining some sort of sling carrier as a back up plan anyway .. Doha isn't the sort of place you'll be doing a lot of walking anyway ( though obviously a sling isn't much good for napping and giving the parents a break ! )