don’t be irresponsible and let your kid end up with COVID then.
Your kid catching covid is not necessarily caused by any irresponsible behaviour, many have been caught out by pure bad luck.
It’s even easier to be considered a “close contact”: all it takes is for
anyone (teacher, other student, cleaner) to test positive in your kid’s class and bingo! Close contact. Off to quarantine your child goes, whatever the age, no questions asked.