Interesting question. I rode TT as a single rider but because I had a FP, I automatically went into the FP line. It was very busy Easter/Spring Wk., and lots of "clever" groups of people who wanted to ride TT but didn't want to wait in the huge stand-by lines, went into the single-rider line.
The single-ride line moved WAY faster than I did!!! The CM kept saving over and over again to the single-riders that they would "definitely be separated" -- he was doing it on purpose -- and the looks on many many in that line showed that they thought they might not have been separated.