Forum Moderators: goodroi
If your robots.txt excludes all uninvited crawlers then you are effectively displaying a "trespassers will be prosecuted sign"
The problem comes with enforcing that law!
In principal it is easy, in practice it is expensive!
In addition you have the problem that you want to be seen by the "desirables", but, hidden from the others.
My analogy would be a photographer chasing a celebrity. Where is the line in the sand to be drawn? You want exposure, but only from those that will picture you on the "good side", a very tricky thing to achieve!