guardrail

noun4

1. •
   A rail set alongside a dangerous place as a barrier, to improve safety.
2. •
   (US, Canada) A strengthened barrier installed on the sides of a (usually major) road to keep vehicles on the highway and reduce the risk and/or impact of crashes.
3. •
   (figurative) Any barrier designed to prevent accidents or mistakes.

   • Some worry that releasing open-source generative A.I. models without guardrails could provoke a backlash among regulators and the general public that could damage the entire industry. — 2022
4. •
   Synonym of check rail.