The present method of protecting addresses on TWiki sites exposed to the Internet is to insert a string - NOSPAM - into the address.
Humans can easily see this when copaiong mail and remove it.
In reality, it is easy enough for reapers to have a set of patterns no different from the early spam detectors, and get around this.
Description
The alternative is to use some script or HTML - perhaps charecter references - that makes the address apear visible on a rendered page but uninteligible in the raw.