Say Total 20 軟臥車廂 in a train - Single Female customers go from 軟臥車廂 No1 and then No2, etc. if she prefer 軟臥車廂, while males/couples/family customers go from 軟臥車廂 No20, then No19, etc. until all 軟臥車廂 'sold out'. This way single females can separated from mixed and all/most 軟臥車廂 will be sold out in most cases.
犯罪現象應該不常見，更多的是有些油膩男找搭訕豔遇，素質有比較差，讓人不舒服