Caught in a Lying Web

I swear, as a parent, sometimes you just need to fib. My kids, three and five, are constantly pushing the boundaries of what I let them do. Yesterday, we went to the park, and they begged me to go on the swings without a helmet. It's mandatory for our town parks due to safety concerns, but they felt like it was overkill since there were no other children around to bump into us. I'm usually strict about rules, especially when it comes to protecting my kids from harm, but something in me crumbled under their pleading eyes. I told them that the park authority said we could go helmet-free this time because of the low traffic area and calm weather conditions. It wasn't true at all, there's no way they would bend the rules for us. I felt terrible lying to them, but there was a part of me that wondered if breaking such a small rule might be okay just this once. I guess I wanted them to feel like they could push back against authority in a safe environment. Now, I'm stuck wondering how much damage a little white lie can do to my parental integrity.