In a film from an English teaching youtube channel at 5:40 around, the female teacher is expressing that using "obey" instead of "observe" is a little too odd and strong in the following sentence.
"Attention customers, please observe social distance rules while you are standing in line." (at 5:26 in the film)
After checking the Cambridge Dictionary and Oxford Learner's Dictionaries online, I don't see that point. And in Oxford, it explains "observe something, to obey rules, laws, etc."
So, is it really a little too odd and strong to use "obey" instead of "observe" in that context?