E-mail address reminder in an age of Spam

One of my clients is an interior decorator. We've communicated by e-mail several times.

A couple of days ago, I received an e-mail from an address I didn't recognize. The return address was similar to "Pretty Kitty" at AOL. The subject line was something to the effect of: "Let's get together!"

Not recognizing it, I deleted it.

Yesterday, I get a phone call: "Why didn't you respond to my e-mail?"

"What e-mail?"

I took me a few moments to realize that I had deleted an important message. But, whose fault was it? In this day of increased concern over uninvited e-mail, it's the sender's responsibility to have an e-mail address that clearly and instantly identifies the sender.