Well, in the past I have written posts on muffs and earmuffs, so now I'm visiting another long-standing symbol of femininity, the bonnet.
There was a time when many hats were termed bonnets, but eventually it came to reflect a certain style. Bonnets were commonly worn year-round, providing warmth in winter but during most times, it served the function of keeping hair tidy at all times and free from wind and dust when outdoors. These mostly stem from the pre-indoor plumbing amongst the masses eras of society and if you are in any first world nation, you likely have at least semi-regular access to a shower and hair brush.
This would then place the bonnet into the category of a dated and needlessly feminine item, likely to draw stares and a great deal of humiliation if a sissy was forced to wear one in public. If it ties at the chin a bonnet can also add a second level of security for sensory deprivation, holding earplugs (or the like) in place.