Comment by nonrandomstring

This! Absolutely.

Some tips:

"I'm not comfortable/happy/okay with...."

"Let's explore some alternatives..."

"I think you'll understand why...."

Don't talk to the receptionist. Or even the site "manager". Make sure you're talking to the business owner. If you find it's a big business franchise, call them or write.

When they offer you "assurances", very politely question those

(they almost certainly have no basis... this is the nub of the Fujitsu/Horizon scandal, that somewhere somebody said "just fob them off").

Appeal to their wisdom;

"So, obviously you understand these things, please tell me does it use a hashing algorithm and store...."

"So you understand this system, I'm wondering what proofs, other than verbal assurances, can you show me?"

"I guess you have a degree in cybersecurity, so can you explain..."

Remember you're not trying to look clever, or play mind games, or troll them. You're trying to get them to recognise that the technology imposes a harm upon you (and others) that they may not have considered.

Having established that, that's all there is to it. Because if they won't be accommodating they're saying; "Sure, we expect you to endure that harm as a hidden cost of joining".

And now you have your answer.