I think a beer mug would be better for your tea than the folkie cliche of drinking from a pewter tankard, Charmion...although I have seen someone turn up at a bar with a tankard hooked to his trousers/belt.

I myself have more than just keys hooked to my trousers - when the strap of an otherwise good watch wore out, I tried adding it to my key ring and have stuck with that method ever since.