In the S.E. Hinton novel, The Outsiders the greasers have to stay loyal to one another because no one else will. The socs have it all. They have parents who love them, or at least their parents provide them with material needs to make their lives easier like nice clothes and cool cars. In addition, they have the approval of a society because of the relative affluence of their families. Even the fourth estate gives them approval because even though they are denounced one day as partying too much, the next day the press praises them for good citizenship. The greasers' loyalty is unconditional and honest.
On the surface, Cherry seems like a openminded soc because she talks to Ponyboy as if he were an equal. When we consider this as a deeper issue, we begin to see Cherry as an egocentric character. Her discussion with Ponyboy is about his brother who she thinks is a doll=she'd like to hook up with Soda Pop. Then she invites the greasers to sit with them, but she had to know how angry the socs would get when she socialized with the greasers. Finally, she allowed the greasers to walk them home, and even the most clueless of people would know this was a bad idea especially since the socs were drunk.