So. Last Tuesday, an independent filmmaker claimed to have found footage of a time traveler in the special features of a Charlie Chaplin DVD:
Mr. Clarke has fallen victim to the third classic blunder: never limit your alternatives to what you can imagine.
The population of Hollywood in 1928 was around 3000--not all that many, but that still makes for hundreds of thousands of unique personal moments every single day day, even assuming nobody came in from out of town for Chaplin premiers. In the most filmed town in the world, in all the filmed events of the golden age of cinema, that's a dizzyingly enormous number of individual experiences captured forever, immortalized in film archives waiting to be seen. The idea that in all those countless moments nobody could ever find a reason to hold her hand to her head and smile except for time travel... That's an incredibly narrow view of the world. It doesn't matter whether anybody can tell you what it is. Your worldview needs to include wiggle room for the spectacular diversity of existence.
She's embarrassed by the camera, and trying to cover her face with a coin purse. It's a cold day, and she's holding a little pouched pocket warmer up to her face for warmth. She's listening to a little music box made to look like a cigarette case, a gift from her husband when he came back from that business trip to Geneva the summer before he passed away. She's one of Warner Brothers' first sound engineers, playing with a handmade miniaturized gramophone--a dead end experiment in distributing sound tracks along with film reels; it only has about ninety seconds of run time, and the lack of an amplifier means you can only barely make out her colleagues shouting dirty jokes at the recorder, but the very idea of holding something so unthinkably high-tech is a delight. The subject is actually a crossdresser, who likes the feel of his little velour clutch against his cheek. Or it is a communication device, but she's actually a wholly contemporary agent of the Mi-go, using their arcane technology to report in on her progress tracking the archaeologist who stole their engraved tablet from a Lenape burial mound.
There are literally countless possibilities in the real world, and if we're really going to open up the world of fiction the possibilities become infinite. Going all Timelord in the gaps just makes you look foolish.