Throughout the past couple of years, I have received the e-mail and snail mail for this program. I've checked into it...it's definitely not a scam (it's through the National Dean's List). I'm pretty sure that most members of the NDL receive the invitation.
The Delegation on Medicine program seem great; however, it's a bit pricey. ~$5,000 for 10 day trips. Personally, I would rather have a longer experience for paying 5 grand?!? Just my .02 cents.