Sounds like your right. US carriers are much more liberal in allowing this (not the rules, just lazy phone agents who don't have time to ask why you missed your flight)

OP should plan to be stuck in AUH and charged full fare for his onwards travel if he trys this with Etihad. on other words - DONT DO IT They could and probably will also cancel his return as well. (though that might be possible to get reinstated

Its much more common and not frowned upon as much to try to "beat the system" in the US since the airlines there are such S-um b-gs. But its not as common or ignored in the Gulf where the airlines don't have as much to be ashamed of