It's exactly because they're in-band signaling that they should be preserved. I don't expect copy and paste to change the sequence of Unicode code points. If th

It's exactly because they're in-band signaling that they should be preserved. I don't expect copy and paste to change the sequence of Unicode code points. If the browser "helpfully" removes certain code points then it's more complexity I have to think about. The only change I'd consider acceptable would be changing to a specified Unicode normalization form. In this case the complexity already exists within Unicode, so the browser isn't making it worse.