These things have to be judged on the day.

Rule of thumb is that disables passengers should not be seated in emergency exit rows. We have a - what's it called? - called "CODPIE" to remind us of who shouldn't be in the exit row seats. Alas, I've forgotten what CODPIE stands for.

As for the language thing on the QF flight, that's a bit extreme.

If we needed help in the event of an emergency, we'd ask people in those seats whether or not they spoke English. If they didn't, we'd move them.