I don't think there's a seal or something like that on the box. But when you start up the machine for the first time it'll prompt you to input the settings, so if the DS boots straight to the game selection screen it might been tampered with before.

Master reset = taking out the battery from the unit for a moment

But if you're worried about getting conned with recon set, it's better to get it from reputable sellers.

I dunno lol. Try asking in the Penang gamer's thread:

http://forum.lowyat.net/topic/548806

Most likely it won't. Most third party chargers are fine in terms of the durability of the battery. But if the adapter is out, its out.

I've never really had such a case. But if its loose, then yes it can.

I prefer a pouch though. That is edgy. But not sure who is selling that.

I prefer your pouch than the silicone. It traps dust and other junk in the DSi! It happened to my sister's Ipod. huhu.