No one but a Bungie developer familiar with the code could say if something is easy or hard. Some say it would be easy to disable the emote. Unless the code has been written with the ability to disable emotes, it's not easy. No one probably ever expected the need to disable an emote. There is probably nothing they can do that wouldn't take coding. Coding means coding, testing, release, etc. It's not a small effort. Toggling Trials off is easy and quick. Anything else isn't.