Matt, I tried that recently with one of my own sites, and after a few days I got a warning in my Google Webmaster Tools dashboard that the bot could not access my /search URL because it was blocked in my robots.txt, and I should take action to correct it. So I then unlocked my /search URL, which is in violation of the above guideline, but made the error in Google Webmaster Tools go away.
These conflicting messages from Google are very confusing!