As of Windows 10, the answer now seems to be "yes". Windows 10 includes a feature called Storage Sense which among other things may delete older files in the temporary folder.
Whether or not it will do this can be configured in settings. From experience with my customers it is definitely the case that this can be turned on without end users necessarily being aware of it - perhaps either as a system default or by admin configuration.
There are a number of different categories that Storage Sense may include in its cleanup procedures. Here is a screenshot of the Storage Sense settings:
The last category seems to be the general use temp files on the computer, the relevant portion reads:
Apps can store temporary information in specific folders. These can be cleaned up manually if the app does not do it
I've seen this occur to files which were "old" - based on their modification date - but not ancient. I don't have a specific example at hand but the files were only a few months old in cases I had seen in the past.
This feature does see to affect files in
%TEMP% which seems typically to be
C:\users\username\AppData\Local\Temp. I'm not sure if it can affect other locations, but I wouldn't be surprised.