If something as simple as this can be considered a cartel, then the entire free market system is a cartel.
The whole point is that companies can only communicate with each other in this manner, and not directly, because that would be collusion.
When I have time, I’ll look up the specific legislation, though i suspect it varies by area.
It would appear 0% of lesswrongers were born in May. Which is strange, because I seem to remember being born then, and also taking the survey.