Standard properties , that are not supported on all systems the same
Tags and ratings, "that might want to be removed before sharing with others" (because they couldnt put that stuff in the comments they already didnt use :-)
NTFS files can hold ADS (alternate data streams) this hidden chunk of monkey waste (humor) would be transferred to other NTFS file systems storages, but will be dumped when you go to Fat32 with it. Generally the ADS is not used for anything critical, and it has been discussed for possible security risk it can present.
Basically both could be ignored, and continue, although it might be interesting to see what was going on.
For ADS get some kind of ADS Viewing capability and seeing if it was used for good or evil purposes. Even if it was for evil purposes, it is like other "data" in that an actual executable (of some sort) would be needed to make use of the data for evil purposes.
For tags and ratings, look in the properties of the files, or sort the "details" columns to show more items, use the Hover tooltips, etc.
Robocopy, and other copy methods exist that would drop that data without popping up the requester.
My normal system had very limited use of the ADS on some files (being used for good). some of the system files had tags on them, other than that, the scans I did, did not show it on "every file" and on "downloaded files" and stuff like that. Hijackthis, has a ADS scanner. I know very little about this, so I would be interested in anything you find out.