I think it's just beyond ridiculous that this issue happens at all. I never had this w/my 3G or 4, but for it to be something that has obviously happened in the past and is *still* happening means that Apple needs to get their butts in gear to make sure it doesn't happen further in the future.
I'm certain I could get my SIM card out, etc., but my question ultimately is: why should I? (or any other customer, for that matter!) Granted, complaining about it obviously hasn't brought a solution from Apple, but IMO it really shouldn't be something where the customers have to either (1) attempt to fix it themselves or (2) spend yet more time w/either Apple or their phone companies' customer service people. Apple should have been making sure it wouldn't happen before they released the phone in the first place, especially given that the problem had occurred in previous phones!
I'm taking my 5 to a local AT&T store tomorrow, b/c I'm tired of the stupid thing "deciding" that there's no SIM card while it's simply lying on the table beside me. It hasn't been dropped, or had anything else "happen" to it. It's about 10 days since I finally received it, and it's been doing this for the last several days.
Personally, it just bugs the heck out of me that a product with this much anticipation and release mania and this sort of cost on a regular basis is having this sort of lame-brained issue!!