Well we are getting away from Mike a Lauren a bit, but in general I have to agree with Don Draper that it is socially polite to convey your feelings to someone who sends a request.
For example, there was a hot chick I met at a party. We exchanged e-mails. I e-mailed her a brief "Want to get a drink?" and got no response. So then a few weeks later I'm at another party and run into her again. This time she is drunk and acting very sexy to everyone. She does the hair twirl thing, talks about different guys she's banged, and what sexual positions she likes best. Lots of eye contact. Granted she was hammered. So I sent her another e-mail, also brief, this time saying it was good to see you again. You know, if you are flirting with me with the sex talk, let's not beat around the bush here - invite me out for a drink and then we can see what happens. So after a day she replied with a brief e-mail and said "Sorry, I don't like you 'that way' and am not interested. If you want to chat at parties we meet up at because we have mutial friends, that is cool, but I'm not interested in more as you're not my type." So I stopped communicating with her - asked and answered. I did meet her again at another party 3 months later and while it was slightly awkward at first we both got over it and chatted in groups about this and that.
If she had ignored me instead of comminicatingm well, hey, there is the 0.0001% chance she might have been abducted by aliens LOL. Seroiusly though, guys need to ask and girls need to answer - it makes the world a more polite, easier place.
Back to Mike - it was pretty obvious she wasn't responding to him by not returning his e-mails and phone messages - after only one date many girls do that nowadays as a communication tool when they are not into the guy and want him to fade away.
I know girls who say they go crazy for a week after a first date when the guy doesn't call or text them back, then after a week give up that he will. When they e-mail him he responds that "I'm busy in Tokyo on work" or something, but on his Facebook is posting that he is in Toronto hanging out with friends. He clearly hopes she will get the hint he isn't interested in date #2 and go away.
It would be nice if in life people of both sexes would respond to requests without using the wall of silence, as Don is saying. We don't live in a perfect world though.