Inaudible audio guide

This happened once a month or so at a site where I worked with hand held audio tours. We would get a coach of old dears, some of whom instantly shoved the handset in a pocket and ignored it, some of whom stabbed buttons and confused it, and some of whom eagerly listened to every word going. 
And the one who forgot that they needed to put their hearing aid on for a change, or turn it up.

(Brilliantly, there are a couple of handsets which are screens, with the full tour in British Sign Language, rather than just offering profoundly deaf people a print out of the script.)