For the past couple of days, the Internet has been literally aware of film footage from 1928 offering conclusive proof that time travel is real and happening. A traveler was caught off guard on camera using a modern mobile phone!!
Yes, based on these few seconds of footage of a manner similar to what we would associate with that of talking on a phone, we can reasonably conclude that the lady invented time travel, traveled back to the 1920s, went to the trouble of dressing up in period costume, and somehow forgot to not do something obvious like using futuristic technology in public space. That's not the only hole in the proposition. What network was she supposed to have connected to? Did she build the infrastructure herself? And once time travel eventually becomes possible, I'm quite sure we'll have progressed past hand-held mobile communicators of this sort - we already did a long time ago as concealable earpieces coupled with Bluetooth have been a reality for years. Given the availability of a hearing aid ("carbon amplifier") that would fit the face in a similar manner to a mobile phone since 1924, the idea she's a time traveler caught off guard talking on the phone starts to fall apart at the seams.
Clearly the only logical conclusion we can draw is that at some point in the future, there's a kind of Y2K type disaster waiting to happen and the only way they can avert it is to use a specific kind of technology only used in the original 1924 Siemens carbon amplifier. So the time traveler went back to 1928 (a few years after release so she could be sure there'd be sufficient availability), bought a carbon amplifier, and wanted to test it to make sure it was working before bringing it back to the future. And that's when she was caught on film!
In your face, time traveler!!