The pressure you want to ensure they comply with is going to be out of their sheer will and I am sure you are not new to the crypto world at the same time not unaware of the time of BCH fork. It has been a rule that even when there is not fork that you should always keep your coins where you control the key and this is always more pronounced during the build up days to the fork happening with various threads that show up on how to claim BTG which you are obviously not ignorant about.

Good luck in getting others join your course and hoping that Kraken will bend to your rules and mostly if you have learnt your lessons to always keep your coins where you have the key.