Sounds plausible enough to me.

I don’t read the license agreement of every bit of software or the privacy policy of every website, after all.

I think this is more akin to reading the rules of a formal assembly before participating (eg.: a senate or a formal committee). These guys do chess events for a living. :shrug:

I’ve competed in many running races, and I’m not sure if they even have written rules. Presumably they do, but I’ve never read them. You don’t need to, everyone knows what a race is.

Likewise, I use GPL software daily, for a living - doesn’t mean I’ve ever read the license.

It depends on the race, sometimes there are rules that might surprise you. One that I recently signed up for has pretty specific gear requirements for 10k/21k/42k/60k. Trail races can have strict rules as well, like the type of compass and nutrients you need.

Exactly. They play chess for a living.

You need to care about the bits around the actual chess playing, but regulations for these things are overwhelmingly made of "play nice, be reasonable, don't be a dick" rules. If you try to play by those high-level rules, apologise if you break the nitty gritty of the low-level rules and fix things at the earliest opportunity, it shouldn't be a big issue. Also, things like dress code can easily be a "not an actual rule, just convention" sort of affair.

It’s very common for sports professionals not to have memorised the rules for every aspect of their sport.

They’re professionals because they understand the game and are in the top 1% of people who play it. Not because they are the best at memorising rules. The latter group are people Who become umpires/referees instead.

One can be a professional champion and referee and professional referee, all at the same time, just not in the same game event.

Sure, but I feel you’re missing the point with that comment.

I get paid to attend conferences for my job, I rarely read the detailed rules of the conference and venue. I assume they all say common sense stuff and are mostly the same. It's no different for chess players

I remember Hikaru saying such things too, on livestreams (twitch or kick). More than once.