Source of Image: Bert Tan

Just saw this image in a post by Bert Tan from the MHHC group. This is a sculpture found in China Square.

In the post it was mentioned that only Nyonya prostitutes would use the service of a trishaw. No women would want to be caught riding one as they would be mistaken to be in profession of prostitution.

Can anyone enlighten me about this? If the trishaw was a public transport of those days, why can't any women use that as a mode of transportation?

Any sharing would be appreciated.