They put them on other flights, CL, rather than voiding their tickets. And they also gave them vouchers for a free flight in the future.
I would also point out that many of these teens pulled the victim card and blamed Southwest for being anti-Semitic (nice lashon hara guys), rather than taking responsibility for their own actions.
Oh, I get it now. Thanks! I agree, they should have just voided the tix. And refuse to sell them new ones unless they agree to split up into a bunch of smaller groups. The only problem I see is the possibility of stranding minors.