That seems short-sighted, to put it mildly! It’s good practice for any personnel in public-facing roles to have some kind of conflict resolution training, IMO. I’ve had a quick look online and found some courses (no idea how good they are, I’m afraid) that are as little as two hours and as inexpensive as £25 per person. You’re doing the right thing by continuing to push the point. Tbh they ought to have risk assessments to deal with situations like this – you could try asking to see a copy.