Technically it is permitted, but practically it is not done especially if you are traveling. This was an IPF and their rules state that the Technical Committee and the local organizer are responsible for appointing spotters.
I've never participated in a championship but all IPF and other federation meets I've attended or participated in were mostly local volunteers because it's easier to count on them to show up, and they know each other so it's easier for them to work together (maybe more important for loaders?).
Hosting a meet is a lot of work, so your club pays it forward by hosting meets of their own giving people more opportunities to compete.