Save yourself the time of driving around. Instead apply online everywhere and then follow-up via a visit to the store or a phone call. Say, "hello, my name is John Doe...I submitted an application a few days ago and was wondering if anyone had the chance to look it over..."
The person will then know who to transfer the call to. I was a grocery store checker once, it was kind of fun.
if it were for a sports authority, pizza hut, or albertsons-- I'd pick whoever followed up on their application or whoever had the strongest application. I wouldn't dress in a suit and go ask for the manager in a ski shop or sporting goods store, unless I wanted to look like the opposite of the type of person they were looking for.
There are positions in which this might be the best course of action, but from the OP, I took it this wasn' this best route.
If you're going for a higher level position, chances are if you go in and ask to speak with the CEO, VP, President, or Manager-- the secretary or receptionist would screen you anyway. I took it by the OPs post that he was looking for an entry level checker or cashier type job.
I agree with your advice for certain positions, but I wouldn't say avoid my advice whenever possible-- i do have some real world experience.
Sno.Say, "hello, my name is John Doe..