My local shops have a 4x rule where if you increase your bet more than that it triggers a shuffle (only for double deck). I'm not sure if they would allow you to 4x one bet after another since I don't play the double deck at all. However, from what I can tell, they're very shoddy when it comes to enforcing their countermeasures. I heard stories of why one long time counter stopped playing at this one place and apparently the issue was NMSE. However, I've definitely wonged in a few times before.