Stupid People

I'm a bit of an eBay fiend and tend to sell off items when I have a clear out and need to get rid of them. We're on broadband now and it's clear I'm never going to use my old dial-up modem. It's quite a good one so I put it up for auction here.
The good thing about eBay is that it's a community. People can ask you questions about items if they're interested or want more information. Part of my job on Web User magazine involves answering reader technical problems, so I'm used to unusual or stupid questions. But one prospective buyer managed to hit a nerve with his emails. I'll provide them and my answers in full below.

Dear meejaboy,
Is this modem in full working order for all functions? Is the "power lead" mentioned in fact a power adapter, and is this also in full working order? Are you able to include with this modem the lead needed to connect it to the telephone socket without extra charge?
Yours sincerely, eBay user post_haste.

Matt Chapman wrote:
It used to be the modem I used to connect to the net so is in fully working order. We got broadband so I don't need it anymore.
Not sure what the difference between a power lead and a power adaptor is. In layman's terms, it's the thing you plug into a wall power socket to make the modem work.
Yes the auction includes the telephone socket lead. That should be on the list, I'll add it to the bottom of the listing now.

Subject: Re: Question from eBay Member: US Robotics external 56K Message Modem *99p no reserve*
I wasn't intending to be obscure - modern US Robotics external modems require a low-voltage power supply, which is often, but not always, a 9volt AC supply rated at 1amp. They sell their own transformer (which they call a power adapter or power supply) for this purpose, but there are different adapters for different modems, so one needs the right adapter, and it needs to be in working order, as they cost well over £10 to replace.
It would seem from your reply that the adapter you are including is the correct one, and is in working order. Can you confirm that is so? Also, is the modem/adapter still under warranty? I ask because some were sold with a lifetime warranty (especially if originally bought as a separate item).
Yours sincerely, eBay user post_haste.

Repent in _haste

OK, is it just me or is this person really stupid. He did help me out by making me realise that I'd missed the telephone socket lead off the list of items up for sale. But I'm selling an electrical item with a power lead. Is it too big a leap to think that might be the right power lead for that item? I'm normally nicer than this, but below is my response.

You'll have to excuse me if I seem like I'm taking the piss, but I am.
I'm selling a modem. I include the words power lead in the auction. How likely is it that this is the thing you need to power the modem? I'm thinking extremely likely.
And yes the modem works. Of course it works. Who would actually sell something they knew didn't work and expect to get away with it?
No offence, but please don't bid on my auction.