I saw this ad last year and after further research discovered they wanted to see your artifacts, and would be taking them away for further examination. I personally don't like to see my artifacts walk away. READ THE FULL ARTICLE.
We've been to several of these artifact ID shows are they're well worth time spent. No one tried to take, buy, or otherwise confiscate artifacts. I was given useful info on the ones I wasn't knowledgeable about and had confirmed those (like Indian made gun flints) that I was pretty sure of. Plus got to see a lot of neat points that never make it to shows or are seen on websites.