How "anti-spam solution requiring sender validation" fail?

Recently, in reply to my email messages to three business contacts, I received messages back from their anti-spam solution, basically asking me to authenticate as I wasn't on recepients' permitted email addresses. How many people, who receive such messages, bother to go through this extra step? I didn't because... It was amusing as one of the message was to an anti-spam solution vendor. The other two were to service providers who were promoting their services at an event, I attended.

How many business leads and prospects are lost by companies who use such anti-spam solutions? Are these businesses aware of lost opportunities because a prospect got a "sender validation" reply instead of answer to his/her questions and decided to go to their competitors?

#1. This solution will block email communication from new business leads and prospects.

#2: You wouldn't generate any new business through email communication as you just eliminated this method of communication from new contacts.

#3: This solution may provide you detailed statistics justifying amount of time saved with this solution but you will never know how much business, you lost, because of additional hurdles "sender validation" process places between you and your potential customers.

#4: This solution may provide you detailed statistics on the messages blocked but most likely it will be reviewed by an IT person who has no clue of how specific messages relate to business activities/process.

#5: Your online/offline marketing efforts to reach out to new prospects will produce low results as some will elect to communicate through email and your "sender validation" will turn them off.

#6: It is a good solution ONLY when you are going to communicate via email with your existing clients/contacts and you are the only one who is allowed to initiate the new email communications with someone else ... wonder how will it work when both parties employ such solutions ... guess you will be using another mode of communication for first contact.

#7: This solution is a good example of how technology can prevent you from doing business using Internet.