For no visible injury and the cause of injury was unlikely to result in a major head injury, I do a quick neuro check, ice, observe for 15 minutes, then send a note and usually a phone call informing parents regarding head injury s/s. I don't keep them for 30 minutes generally. If I have concerns that make me think I need to keep a close eye on them, I'd rather just refer them for a medical evaluation.
In reality, no, every bump at recess does not need
a neuro check. They would not be getting one if it happened at home, and I would not be doing it for my own kid's minor bump. But, since we are taking care of other people's kids, and we DO have the knowledge and expertise to assess for head injuries, I feel like it is my responsibility to assess every single potential head injury to rule it out. I would rather do neuro checks on 10,000 that turn out fine than to assume one is a minor playground injury and miss an actual concussion. So yes, I do a basic neuro check on every little bump that comes my way