In WoW: Forever, any bind-on-pickup drop will grant its transmog appearance to all eligible looters when it drops

Just announced at the WoW Forever panel, explicitly noted as a deterrent to ninja-looting where a Warrior could roll on a leather helm for the mog.

In modern retail, this is likely not necessary but it's an interesting change.

https://www.wowhead.com/forever/news/forever-transmog-items-dropped-in-dungeons-unlock-appearance-for-whole-group-382865