The Stasi would have still found out that he fled the republic as long as he entered in West Germany under his real name. His girlfriend would still have been interrogated etc, perhaps a little less since it would have been easier to feign unawareness with her boyfriend just disappearing out of the blue.
The real beneficiaries would have been the students helping him and the teachers. They would have been able to travel to the GDR (to see their friends/family) since they likely wouldn’t have been connected to the escape.
The bravery the girls displayed was for defying the East German dictatorship. It could have ended much worse for them had they been found out before crossing the border. They did put their fellow students and teachers at risk, no doubt. But after the fact it seems pointless to punish them for helping a fellow human being escape dictatorship. Aside from maybe discouraging future travelers from such actions.