It's not really an under-the-radar hard sell. Here's the page in question, which nobody in this thread can be arsed to look at: http://cl.ly/image/2V302C3j290B

Now, I can see how one might miss the fact that this will send an email.

Things you can say if you're being intellectually honest:

  * The fact that this will send an email should be more prominent
  * The content of the email should be more explicit
  * The tone of the email was overly personal
  * The from: field appears as if it's from the person, not FD

Things you can't say if you're being intellectually honest:

  * The form is opt-out
  * There's no copy on the page indicating an email will be sent
  * The copy on the page is hidden below the fold
  * The copy on the page is worded designed to mislead the user
  * The fact that clicking submit will send an email is obscured
  * There is no indication about the content or tone of the email that will be sent

Looking at this page, the most aggressive case I can make is for a slightly confusing design that should better highlight the consequences of choosing vouchers. It doesn't seem in any way misleading and doesn't show any of the fingerprints of someone looking to trick a user into accidentally emailing their friends.