Source four safety catch

Hello! I've been working we a theatre lighting electrician for about 20 years. I recently did some work at a community college and they told me not to attach the safety cable to the safety catch on the fixture itself. They said that the light gets hot and cool so much that it makes the material brittle and that it could break if the fixture falls with the safety attached. I never heard this before and I strongly disagreed with them but didn't want to make a big deal about it. I couldn't believe that they would rather have nothing attached to the safety catch rather than something. Even if there was a chance it was brittle and could fail. Could you please tell me if there is any merit to this? Does it get brittle over time with repeated use? Thank you!