I think a wrist band is a good idea.
I only ever used to wear the wrist band when out running, because I felt that was when I was most at risk of hypo-ing and needing 3rd party assistance (I've never actually had a severe hypo during exercise and have only ever required 3rd P assistance when at home to at work - so those assisting already knew I am diabetic).
I really really hated wearing the wristband though. So I gave up and got a tattoo on my wrist instead.
I think the tattoo has been relied upon, indirectly, by a first aider once as a colleague noticed it and commented on it at the tea point one day and, as he is an ex-doctor, he got called upon to be in charge of the first aid when I had a pretty severe hypo at work a few weeks later. It always gets praised as a good idea when I'm having blood taken, lol. I guess the aim is to never have to rely upon any medical ID, but given the number of times I seriously contemplated catapulting the wristband across the road when running, if that was all I was relying on I bet I wouldn't be wearing it when I needed it. At least with the tatto I can guarantee it's always there! Should there be a miracle cure I'll have it creatively amended