Official parts freely mix / and \ when specifying sub-parts on type 1 lines. That's not going to change. However, as you point out, all the Name lines currently use \. I don't have a problem with requiring them to use \, although I strongly suspect that the existing name lines are algorithmically generated by the parts tracker, since 100% consistency on non-critical items is something that's rare in the parts library due to its long and varied history.
I'd also like to point out that, except on the command line, all versions of Windows fully support / as a filename path separator interchangeably with \ (although I think UNC paths have to begin with \\, and not //).
I'd also like to point out that, except on the command line, all versions of Windows fully support / as a filename path separator interchangeably with \ (although I think UNC paths have to begin with \\, and not //).