If someone is clueless enough to think (or believe!) that an old SCA helmet is a real antique, then they deserve to be taken.As for the second one, this is the best case of Indian manufacturing gone wrong. All the Indian manufacturers steal designs from each other, generally in the form of a piece out of inventory. After 8 or 9 generations of copying from copies, what started off as a standard bad interpretation of a bascinet turns into this mess. It's like when we were kids and played telephone, and the message "Meet me at the corner" turned into "Little Jack Horner".
All joking aside, the most disturbing thing about these sales is the claims the vendors make. Taken directly from the Ebay page:
This is an accurate reproduction of the Bascinet Helm with an attached Aventail.
A Squared Armory offers the highest museum quality replica weaponry on the web.
The sad and scarey part is that claims like this more or less mean that the terms "museum quality replica" and "accurate reproduction" are absolutely meaningless.
Unfortunately, this trend is not confined to armour and weaponry. I've noticed that almost all costumes are now "historically accurate replicas" which are suitable for "living history and reenactment" use.
This is the "Phillip the Good Doublet" by Sofi's Stitches (http://www.sofisstitches.com):
Here is the description from their website:
This outfit is a reproduction of one worn by Phillip the Good, Duke of Burgundy from 1419 to 1467. (We accented it with woven instead of fur.)
In the painting, Phillip wears a belt, simple poufy shirt, hosen (tights), a wide necklace, and tops it off with a turban.
We recommend wearing with the Classic Renaissance Shirt, our Ring belt, hosen and breeches. You can substitute the hosen with long socks to wear under the breeches.
It's sad, but I suppose now that shopping is so effortless and vendors have no compunctions about making false claims about their products, "Caveat Emptor" applies now more than ever. 
Gwen