I used to argue with those in my class who played with the particle accelerator instead of doing their philosophy homework. That was going on half a century ago. How would they measure decay of a meson? Would it be by noting where it happened and thereby that it must have moved farther down the tube because it was going close to c and its timescale was stretched out of whack? Or was it going faster than c and for that reason moved farther down the tube before decay? How can you tell the difference?
Were the meson travelling faster than c, then there would be a standing wave (bow shock) in the ether (detectable, anyway.) This is analogous to the sonic boom emitted from a plane (or car) moving faster than the speed of sound.
Cerenkov radiation is an example.