Is there a wrong time to exchange cards?

I was talking with a client the other day about a networking event he attended recently. He mentioned that he had wanted to approach one of the speakers after the talk but didn’t know what to say.

It is sometimes awkward to approach a speaker, especially when people are swarming around, wanting a moment’s attention. That isn’t always the best time to make an impression, but you can certainly plant a seed for later.

So I suggested that, after saying something like, "I really enjoyed your ideas," he could say, "Let’s exchange business cards.”

There was a moment of silence and I wasn’t sure if he was still there.

Then he said, "Are you kidding? Why would he want to exchange business cards with me?"

Anyone else ever feel that way?