This seems to be a new trend, which is expected to affect ABC圣女 who are dating 30+/-小中男/小白男.
20+小留女 have known how dirty established men in China can become; and thus they like to stay in US after graduation. They know they can't compete against 20+小中女/小白女 for 20+小中男/小白男. After all, some 20+小中男/小白男 are not eager to tie the knot too early and like to do so in their 30s when their careers are well settled. Therefore, 20+小留女's likely targets are these 30+/-小中男/小白男.
So if ABC圣女 are dating 30+/-小中男/小白男, a 20+小留女 can easily win the battle. This happened to Jenny recently(her man was an even older 二婚白男 but she still lost him to a 20+小留女). And I am afraid that by the time of the coming May graduation, my town may see a couple of more cases.
Lesson 3: 小中女26前集中精力on marriage with like-age 小中男/小白男! Don't drag on with man until you are too old to fight your new competitors--20+小留女!