If the rule says they are to be confined to their own side - then make sure they do. If distance does not allow a safe ODC, keep them in DBT. No matter what you want to think about it if you allow deviations and someone gets hurt as a result, you have now absorbed some amount of liability. That's why the rules are written the way they are. If you follow them, you are covered - if you don't, you open yourself up wide. If you want to call it CYA, so be it. Just remember, you're also covering the a$$ of the kid who wants to cross the line, but you hold him back.