Most of the guys on the beach I've talked to don't really play in what we would call 'in tune', as in 440. I can't really imagine them stopping to tune up with a machine, as I'm sure they have to adjust often simply because of the climate. A few of the better musicians that play gigs around would certainly appreciate them though I'd imagine. And I'm sure they'd love to mess around with a capo too. Harmonicas, guitar strings, and guitar straps that I've have brought have all been appreciated too. Hope that helps, awesome that you're doing this!