Highest record.

I don't know if this has been discussed before but It is a well known issue that some players lower their ELO to play in lower categories. I propose that all the players can only play tournaments with the highest ELO acquired ever. (Sorry English is not my native language)

Yeah that's called sandbagging. Now a few concerns:

1) A strict cut-off by highest elo doesn't make sense, people fluctuate some-what.
2) Players can stop playing for some time and become worse.
3) Mere chance makes it conceivable that you can win a few games in a row because your opponents each time aren't playing to the best of their ability, inflating your elo (until it drops back down a few games later). Or even the very act of sandbagging itself from above, leads the opponents of the sandbaggers to gain elo.

Well sandbagging would not be a problem if mods banned accounts that were sandbagging. They only give out warnings to player who sandbag if you want an example I have found probably a dozen accounts of sandbagging and as far as I know only one has been banned.

I wish an intermediate solution like "Ban play from UXXXX tournament existed"

@Bobkingmen3 I don't agree. Most of the people I report are sandbaggers, and I get the popups for 'a player you reported was banned'. Whether they were cheating on top of sandbagging I don't know, but I'd say they do ban sandbaggers.

people who sandbag online tournaments are pretty sad and shouldn't be worth anyone doing anything about. On a similar note though it shouldn't be an issue for players playing against a player of a higher level than they are, rather it should be something to look forward to. That is if you have any intention of improving at the game anyways.

I've encountered a few sandbaggers. I often see they've played thousands of games without getting caught. But when I report a sandbagger, there is a high chance Lichess will follow up on it. Maybe people just aren't reporting sandbaggers enough?