I remembered another detail about the limitation to 4 games per day for regular rated tournaments. When we updated the conditions for regular rating a few years ago, we were faced with a few junior organizers who had been submitting fast time control events for regular rating, contrary to the rules. When I started auditing them, there was considerable push-back and there were cases where they simply stopped advertising the time controls so that I could not enforce the rules.
One way to spot fast time controls was to look for one-day events with lots of rounds.
This is less of a problem today but I think it is important to be vigilant.
There is always pressure to water down the requirements for regular rating. We are seeing this now with online chess. I agreed to the COVID-19 bonus and I think it is a sensible thing to do but the original concept that was presented to me was significantly more generous.
There is also always pressure to pump up the ratings of "under-rated juniors". The bonus system was introduced primarily to address this issue and it has been working quite well.
It took Bobby Fischer 5 years to get good. Today, many think that a single tournament is enough to identify the next Bobby Fischer.