In Japan it's generally not considered cheating, so it's mostly never even mentioned, if auto fire was used or not. I wouldn't call it "cheating" anyway, the question is rather if it should be mentioned, and for me personally it depends on the game and the kind of challenge you're aiming at, weather such an indication is required.
Like when you play Viewpoint for score, where auto-fire changes the whole difficulty level, even the whole structure of the game. There it should be mentioned. It's still not cheating, it just becomes a separate category. In this particular case with Pulstar, the challenge is called "no power ups" and I'd only argue that AF counts as such.
But never mind, since there's another important category which seldom gets mentioned. Kid Panda already implied it, when he said "once you learn the lines...". Exactly how did this guy learned them? Back in the days, players invested their own hard earned money to learn a game. They literally quarter munched a machine, till they learned the lines.
Consequently, a one coin clear required either a big pocket or natural talent and in both cases, a now unimaginable amount of patience. It also required you to dedicate yourself to just a single game. That was the case, until the age of emulation provided TAS, auto-save functions, i.e. computer aided learning, which forever replaced talent as an extremely potent catalyst. Current players can learn the lines with no expense and about ten time faster, if not more.
They also don't need to dedicate themselves to one game, that's why it's possible for one guy to hold records in several games, one-cc whole libraries or waste time for fascinating, yet somehow hollow challenges, like this one here in Pulstar. Don't get me wrong, I'm not opposed to progress or such challenges, I just learned to hold my respect for past arcade pioneers and doubt we're dealing with one here. The times to drool over any anonymous video with no background information whatsoever are definitely over.
