I think the idea is that given a large corpus of filtered and unfiltered reviews, you might be able to reverse engineer signals in the algorithm and game the system. If that's your end goal, you and the software you write is likely to ignore robots.txt directives.
A quick and dirty solution could be to add something to the page using javascript after the page has loaded and only let the link work if that variable exists (and check the value of the key with the server, if you wanted to be more cautious). Not a complete solution, but a first step and invisible to the user (and a pain in the ass to a robot)
A robot scraping yelp's deep data is going to be site-specific, and having to scrape another javascript variable is not much more than a slight speed-bump.