Is the Advance AutoParts guy confused about my battery installation?

I have a 2001 Honda Accord EX. About two weeks ago, the battery died and I got AAA to give me a jump. The AAA guy said I probably need a new battery. So I go to Advance Auto Parts today. The Advance guy does a test first and finds my battery is fine, but needs to be charged. I decide to just get a new battery since I'm not sure how old this one is (I'm the second owner). After hooking something up to the inside of my car for 5 minutes, then disappearing inside for another 10, then Advance guy comes out and tells me he can't change the battery because there's an alarm on my car and disconnecting the battery will erase all the codes. He says that if he did replace the battery, the car won't turn on and nothing will work. He told me to go to my dealership for a new battery.

I had my battery die two weeks prior and did have to punch in my radio code once it was jumped, but the car still turned on. Is there a second code I should be aware of? Or was the Advance guy just very confused?

I really don't want to go to the dealership, so if there are multiple codes, I'd like to find out how to find them. Like I said, I have my radio code.

I've always wondered about that code thing. I'm on my third battery in my 2000 model and have never had a problem with the radio. Maybe they're talking some upscale thing?

Dude does not know what's he is doing on both matters.

I wouldn't say the bloke doesn't know what he is doing but he should have learned a bit more before he started dealing with customers. Firstly, just because a battery seems flat, it can still give a reading of 12 volts on a volt meter. The only real way to test them is by applying a load. A good battery should be able to hold at about 9 volts under starter motor load. As for disconnection, there's a little thing called a small jumper lead that can be attached to both connections during change over to stop the vehicle losing power to the electrics, thus having to avoid reprogramming radios and having computers reset themselves. If your battery has completely collapsed, that may be a different story. Be aware that a load tester can sometimes destroy a battery that is in its last death throes.