Well it would be best to put it on the first file loaded on remotes on the first line, because even if you put it in a remote file, by itself, and before that there was the same event with a halt command, then it would never trigger.
Rubbish.
Dont go telling people stuff u have not even checked on yourself.
The only way a another scripts HALT effects your own event is if you specificly coded for it to not run with a ON & or you are testing the $HALTED identifier.