Your companions get largely ignored by NPCs unless they specifically have something to say and possibly even then their presence is only marginally acknowledged.
The first video game about Ignored companions was released on April 12, 2005.
Electronic Arts has published all these games
Can also be extended to summoned creatures in cases where such should draw significant attention from others, such as having a throng of anything following you around or a notable monster of any sort walking around in monster slayer's guild or similar.
Should be considered outside of their associated plots, so even a significant companion can be ignored when brought along for some side questing.