I don't think Microsoft are that clever or malicious in that way. There are third party drivers available and I don't know what all the Linux parts in Windows these days are able to do... So it's definitely possible. But I think you're looking more for a targeted attack with this. Like an agency or a hacker singling you out because they know you have valuable data on that filesystem. But Microsoft's business model is more fishing for the easy targets and funneling data en masse, not the niche stuff... That might change at some point one day once the Linux subsystem automounts filesystems or something like that.