Board Game Arena

Sorry if this has been discussed before, I couldn't find anything similar.
Before posting a suggestion I would like to check wether it's not already
in place and if people think it might be useful.
I came across a discussion (I cannot remember which one) where a player
was saying that he was able to play in arena multiple times with a friend
just by syncronizing the game request (not 100% but very often). The
behaviour didn't sound malicious, they just like to face each other and
the arena format. However I think this is not appropriate for a competitive
environment and against the arena philosophy to match player randomly. Morover
it can be easily exploited.

My suggestion would be to keep track of the last say 10 players met in arena
and prevent rematching with those. Ten is merely a concrete example and might
need to be adjusted for each game. It could also be mitigated allowing rematch
after a given time and the requirement be different for real time and turn based.

Yes, this is a known issue. Arena matchmaking can be rigged. This is an inherent flaw of Arena and it can't be fixed without hurting honest players. Arenas with large playerbases are already somewhat protected from such rigging. But if we prevent rematching in small Arenas then honest players will have much harder time finding opponents, while cheaters can just create as many dummy accounts as necessary.