The way I see it, the info from andrew11121 and kiwikittens has to be correct. There's no way they'd ask you to change domicile to qualify for tax free status. It seems that they're just closing a loophole for people who aren't paying tax on earnings earned on business trips. People living abroad, not just travelling on trips (like most of you guys I guess) will continue as you were.
The way I see it, the info from andrew11121 and kiwikittens has to be correct. There's no way they'd ask you to change domicile to qualify for tax free status. It seems that they're just closing a loophole for people who aren't paying tax on earnings earned on business trips. People living abroad, not just travelling on trips (like most of you guys I guess) will continue as you were.