As Leslie indicated earlier, most of our internet programs allow for sending every message as simple text files without formatting in html. But they also allow for reading certain texts back the other way around.
My own url in my signature file which I cannot get Netscape 7.0 to use is simple text typed in without any embellishments. When I received my messages back from Photoforum using 4.7 that text always appeared on my computer as an html link.
Perhaps the apparent problem rests not with Leslie's messages as sent but as they are received. If she has her program set to send plain text only then one would hope the program would send them that way. If individual's receiving them, myself included, find that her typed in url is converted and read as an html link, then that takes place at our end and not hers.
Peace! Sidney