Ron,
I'll echo e's comment, in that it seems that a great deal (and perhaps too much) is being made about "copying" objects made by others, both known or unknown. Let's be clear, however, that much of the attitudes and comments derive from the academic context. Plagiarism, as an academic "crime", has been historically easy to prove, since words and phrases in print are easy to compare, and it's a "strict-liability" case, meaning if your term paper matches up with Mssr. Sartre, you're guilty whether you meant to rip off the prior author or not.
Importing all this into the visual arts is a very different story. An author can put a phrase in quotes and drop a footnote to give a full acknowledgement of the original writer's contribution, and that recognition will last as long as the page it's printed on. Not so for artists. How, for instance, can you comply with Malcolm's comment about giving credit to your source? Do you know the source? I'm not talking about the entire body of Russian ceramics work dating from the 19th Century, but rather the name of the person who made the piece your wife saw? Next you need to establish that that person originated the design and didn't "borrow" it from a 4th Century original that was a copy of a Hitite piece that dropped off a caravan wagon 20 centuries B.C.
But let's make it a bit easier. Let's say you make a wood cowboy hat and let everyone know that you were inspired by Johannes Michelson. Are you in compliance with proposed ethical rules to avoid "Turner's Plagiarism"

? Sorry, Old Chap, but you are guilty as charged!! Why? Because in your zeal to honor Johannes, you left out acknowledging the oriiginal designer, Mr. Stetson.
Oops
Of course, when we go back to our academic example, we see that writers' review committees have it pretty easy because they have the ability to research every prior use of the suspect phrase or passage in books, scrolls, or 5,000 year old stone tablets, and
THAT activity is what those people actually thrive on because they are academicians!!!
So, now that we've questioned whether an honest turner can ever give a complete acknowledgement of the influences that gave rise to a particular piece, lets consider HOW you and I are supposed to do so. Is posting a picture of your piece in the AAW website photo gallery with a nice little blurb about "inspired by M. Mandell" going to be sufficient

? Hmm, nice try, but maybe not. Well, how about a nice little tag or sticker listing the piece and the inspiration? Hmm, maybe, but tags and stickers get lost (or trashed) about 2 minutes after the person who buys the piece gets it home, so all that's left is your name carved into the bottom. Uh oh, . . .Are you now a PLAGIARISER because your truthful acknowledgement got separated from your piece through no fault of yours? The problem thickens . . .
Wait, I have it!!!!!!!
In addition to the maker's name, the acknowledgement (in sanctioned and approved official form, of course) must be laser-engraved into the piece in such a place that, even though the maker's name becomes obliterated from the bottom, the acknowledgement will survive as long as the piece does! Now why didn't I think of that to begin with?
