I've noticed a similar shortcoming with running/gps apps. If you use your phone to track your run, it's usually in a case, on your arm, waist. You are usually sweaty, and if it has been a decently good run, you're a bit tired, maybe shaky. Having tiny buttons definitely doesn't work. Or placing the "Save" this run, and "delete" this run buttons right next to each other is also a bad idea.

While asking drunks to beta-test your app isn't a bad idea, I'd say a better one is to have people beta test it in the context of how/where/when they will use it.