We have something at our house that changes the channel a lot of days during the week to tv land channel 54 here for bonanza. You can be in there watching tv and the tv just changes. I have come in and the tv is off and then turns on to this 54. Pretty crazy. Guess there could be someone close with a powerful remote tunned in, but the tv turning on to this specific channel is weird. Our dogs will also track something quite often going across the room. They will both see it and follow it when there is nothing there. Whatever it is, it never causes any problems and if it wants bonanza that is fine with me.
The TV could be someone with a remote and probably is, but the dogs say something else. Animals pick up many things that humans miss. Sometimes small children do too. If you ever replace the TV with another brand and it does the same thing, I would bet on a ghost of some sort. Until then I would figure on the remote.