Stringent Bathroom Requirement

while I was happy to visit one of my favourite bank's branch, was faced by a difficult situation, I had to go to a bathroom, the security guard showed me to a car guard whom i should request the key for the bathroom from, the gentlemen told me to give him my identity document for me to use their bathroom, so shocked i declined, that i cannot divulge my personal information to a stranger, it is totally unexpected and unacceptable,to request a personal document for use of a bathroom, i then went to the help desk to which i thought i might find help, still the unacceptable rule was held up high, so disappointing, that i now have to travel with my identity document just incase i might need it when i visit my bank and have to use the toilet.