I took a quick look.  Users that have a single address (web wallet usually) will get an error message if they try to do a repeated escrow transaction with the same buyer/seller pair because you will generate the same escrow address.  Good thing you have an error for this , otherwise the release code would already be known to one party.  Notify users to use a fresh address when doing escrow with the same buyer/seller.

  Hmm look like it still let me use the repeat of the address pair.
https://crashcoherency.net/multisig/transactions/10e6517d-9668-45eb-9d8c-9d62c7e48c08
https://crashcoherency.net/multisig/transactions/86737628-a591-4ff5-87f8-25ddbc3513ab