I dont understand the facination with this myself, but here is the deal with the triple-chirp talk permit tone, at least as far as astro/astro25 is concerned...dont know about any other platforms.
First, you cannot get it on any Astro platform without the radio getting a channel grant on a trunking system...period.
Second, the video on youtube was faked...the person who posted it admitted on the batboard to dubbing the talk permit tone into the video for dramatic affect(he was trying to sell the radios on ebay).
However, there is a way to get Astro25 radios(such as the xts5000) to use the 3-chirp TPT without being on a trunking system. It requires the radio to be used through a digital vehicle repeater system or a Quantar repeater that it is tricked into thinking is a DVRS.