Board Game Arena

The intermittent connections can cause real problems in fast-turn-setting real-time games.

In particular in combination with how flaky the site itself has been lately.

Perhaps some kind of notification for players joining fast-pay games from a mobile device that their connection stability and timing might impact the game play quality for everyone?

The quality of a connection does not mainly depend on which kind of device someone uses. Example: When using a mobile phone, tablet PC or iPad at home, I'm connected to my local WLAN, which provides a very good connection. Why should I get blamed, because I use a "mobile device"?

BGA's device detection is not accurate. It will often say that I'm using a mobile device even when I'm on my laptop. And there are times when I actually am using my phone but it doesn't show up that way. Interestingly, my phone is way faster than my laptop...

Well, a player's reputation/karma is far more important than what device they're using.
Just use karma filter, and u'll be fine for >95% of games.