Being from Cardiff and knowing what a damn good night out it is and generally is very good mannered, I dont see any problem with this story or why their parents should be ashamed. The DM always bashes students out on the lash. Our parents probably did it too but didnt have the internet and digital cameras on everything to spread the photos.
So what if they go out and get drunk, they will spend the next x number of years studying, running up HUGE debt, without promise of a job at the end of it, so if they want to blow off a little steam then let them. Cardiff is renowned for a friendly fun night out and usually there is very little trouble, so I say to these students good on them!!