Most people who are getting "KYC & Refunded for the deposit" are "Sportbooks" player. Because, I read in some situation sportsbook player can easily abused like odds or other abused activity as well. Now, If you comparing user who are playing "Livegames or Slot" we always have a small chance to get a "KYC"
Even my self already register a few casino, have some withdraw with high amount money including "BK8" never getting KYC request.
Yeah, the case of slots or non sports betting is pretty rare, even here in Bitcointalk I can only recall one ban case when the player found and abused a security hole in a slot game and won a lot of BTC. Meanwhile, every week or so, there will be one or more case of sports betting. Arbitraging, match fixing, syndicate, is one of many reasons people got banned.
BK8 policy regarding to ban is pretty lenient since they returned the deposit money instead of confiscates/freezes the fund compared to most casinos.