Since you mentioned part 15, I'm guessing you're asking about the rules in the United States.
If you look at part 15 subpart C in detail, you'll see that the frequencies in the VHF I band (44 - 87.5 MHz) have some specific unlicensed uses, mostly related to audio transmissions (wireless microphones, cordless phones, etc.) Since the question is about TV signals, most of those don't apply. The only exception I can see is §15.235, which doesn't specify a specific application (except for saying that it can't be a cordless phone). However, that section is for a very narrow band: 49.82-49.90 MHz. Since NTSC signals require 6 MHz of bandwidth, that band isn't nearly big enough to accommodate a typical video application.
That leaves white space devices as the last remaining option. The rules for these devices are complicated. The available frequencies vary by location and time. The maximum allowed power levels vary depending on the frequency and the characteristics of the device. It's possible to transmit with a range of several kilometers with the right gear, but you have to carefully follow some fairly complicated rules.
Because the question referenced unintentional leakage, I'll point out that it's covered by different rules. Part 15 subpart B has the specifics.