Not just in films - my wife is a fan of Nativity scenes and we have an annually more elaborate one with new buildings, bread ovens, animals or whatever she's made. There are whole shops devoted to the subject in the Mediterranean countries, shows, competitions etc. There is a debate about whether they should be set in late December 1 B.C. or whether current objects should be incorporated.
After all, mediaeval churches, Renaissance paintings and other artworks have key players in whatever they are portraying, whether carved in stone or painted in oils, dressed, with hairdos, even physical characteristics contemporary with the era in which they were created (e.g. fatter women were regarded as more beautiful until relatively recently and before the jet-set emerged and made them fashionable in the latter half of the last century sun-tans were a sign of lower social class, probably because it showed that you had to work - when the economy was heavily agricultural and a lot of work was outdoors).
I'm always amused to see amongst the accessories you can buy for markets in the vicinity of the stable or inn or whatever, stalls groaning with chorizo, jamon and other pork products plus others with crustaceans and molluscs in what was probably a pretty kosher part of town, and more bizarre, an adjacent stall with potatoes, maize and chillies, antedating C Columbus by nearly 1500 years. I've yet to see one of the Kings arriving with his myrrh in a 4200 though!