This has happened with me and can happen with you too.

A drunk man had a seat with me while travelling to Delhi in RAC.While asking for confirmation ,if it was seat or not,the man started threatening me with the sentences such as,'I will throw you out of the train'.He had no senses about what he was speaking.I felt threatened and unsafe on my own  confirmed seat. 

Although,TT changed the seat and other passengers came out for help but this needs a change especially while night journey .

The seat sharing should be with the same gender (with appropriate transgender consideration).It's high time railway authority should look into this.