Downgrading on EK is more common than on other airlines, but upgrading is MUCH more common. (About 70%+ of my EK flights they have had to upgrade someone usually J-->F. I do always travel in peak though.)
I was 12 and my sister was 10, and that was the main reason. (Kids dont know anything blah blah) So they knew the flight was oversold, and in KHI they bumped us down and basically waitlisted us for J (in case of a large # of no shows or missed connection) and they gave us crummy seats in Y accordingly (since we wouldn't be using them

) In Dubai (with less than 45 minutes to departure) we went to the desk and I raised hell with the transfer agent who was rude and unhelpful saying "what do you want me to do, the flight is full. You are stuck in those economy seats you got assigned"
We asked again in the DXB lounge and the people there were much nicer but still no dice. We had a connection to AC so we could not accept VDB and thus were downgraded without compensation. (Their deal was VDB or accept this flight in economy without refund - stupid i know, but it is in their fare rules)
The way people treat kids... **sigh** thankfully from now on, I am much more travel savvy. They have tried it a few more times in KHI but I am far less considerate to their suggestions. Some things they have said
- We have assigned you 2 seats together, but they are in economy. Is that OK?
- We are not allowed to assign you business class seats because there are none left
-They will definately give you the business class seats in Dubai
-They do not allow business class seats to be assigned here in Karachi
Cheers