Why it matters to you
Mild flammability does not make a new system a fire hazard; UL 60335-2-40 builds leak detection and mitigation into the equipment, and many A2L installations require a refrigerant detection system. In Greater Houston homes with air handlers in attics and closets, those sensors are part of what makes the installation safe.
Practical guidance
If a quote includes A2L equipment, ask how the refrigerant detection system is installed and wired. Never unplug, disable or cover a refrigerant sensor, and leave all refrigerant work to a certified technician.