Umm. No. You're wrong. Did you even see it?! It's because no one used it!
Jared, I know you like to stick up for Chessington at every possible opportunity (no idea why), but I don't think it's fair of you to tell somebody they are wrong.
From my experience, SRQs from exits in general don't work. Thorpe Park used to have them on Colossus and Nemesis Inferno exits and they were removed, not due to lack of use but due to it being unsafe to clog up the exit.
From what I witnessed of Dragon's Fury SRQ it was well used, which is precisely why it was removed, large numbers of people were using it it thus clogging up the exit. You could say that this was because staff weren't managing it correctly, or simply because the exit wasn't geared up to act as an exit, a priority pass entrance and a single rider exit. Whatever the answer is, it certainly wasn't because it was under used in the case of Fury. In the case of Tomb Blaster, yes nobody used that one. But Fury's definitely was used.
Chessington also used to run a SRQ on Samurai and I've heard that one was trialled on Dragon Falls for a very short period, which looking back seems crazy now.