New? way to trick a spider

[marten]

I got an idea... not sure it will work.
If I made txt-files run through PHP with an AddType in htaccess i could have a script in my robots.txt that recorded the IP.
Then I would KNOW it was a robot without having to mess with robot-IP-lists.

[MrSpeed]

That may work but I've noticed a lot of spiders that don't look at robots.txt

[volatilegx]

Also some browsers and internet accelerators and such look at robots.txt. And, robots don't always access robots.txt prior to accessing other files. Some robots only access robots.txt once a month or so, and continue to request files all month long.