You could easily assemble it on hover or on click. And bait the bots by putting a hidden element above that if they are randomly activating events, then it disables your email display code. Or any number of tricks to make it impossible for any spammer to harvest your email unless they specifically target your script.

WHOIS isn't meant for soliciting. I don't check it regularly, and I would be surprised if any customers contacted you that way. But that's just me.