I also cut after the first couple of eggs pip. I do want to see what I got, but also check for any issues.
Someone mentioned hatchlings emerging before they absorbed their yolk sac. This happens occasionally, but it doesn't happen only with cut eggs. Hatchlings that cut their own egg seem equally likely to make this mistake. I have never lost one yet as a result, however. I haven't seen any sign that cutting the eggs makes this more likely.