Yes, but our TV sets are neither Canon nor part of the Trek universe in any other fashion. And if they are, why don't we just say that Tuvok wore "lieutenant" insignia all along and that Q manipulated our TV sets to make it look otherwise?
The TV sets do factor in on our perception of the fictional universe in a more direct fashion than opening credits or paraphernalia books. Consider Torres' rank: the resolution of our sets, or of any viewing media we might use to view the episodes now or in the future, do not allow us to discern whether Torres wore two bright slashes, or two dark ones, or one dark and one bright, for her Maquis rank marker. We're thus left with a great freedom of interpretation - and we have reason to do our own interpreting, since the slashes in reality apparently fluctuated quite a bit between those alternatives. It would be different if we evoked the TV set clause to try and pretend that Torres wore a red uniform, as this would only apply if we had especially crappy TV sets.
It would be awkward to try and say that O'Brien wore chevrons when the episode has him wearing pips. But it's quite plausible to argue that these shiny little pips are of a color different from the one intended - a great many props have ambiguous colors and feature "color errors" in certain episodes, but can be ignored and interpreted as error-free because the TV resolution simply doesn't suffice for proving the errors.
Lets face it the wardrobe dept. fucked up, it happens. It even happened in BSG when Tigh had an Admiral rank in one of the earlier season 4 episodes.
