What semantic notions underlie 遮 (obstruction) with 辶 (walking)? CUHK doesn't proffer an etymology. I quote Yellowbridge. How are my two guesses?

Was Ancient China so lawless and unruly that you needed to shield yourself, even when just sauntering?

Did Ancient China rain as China does now, so that you always needed a parasol? In Cantonese, 遮 means parasol. As of today,  Three Gorges Dam purportedly is overflowing.
One of the meanings of 遮 is &quot;obstructing&quot; - getting in the way of somebody else, thus preventing them from walking. That might be the reason why 辶 (walking) was chosen as the semantic component.
As for the usage of 遮 in Cantonese: It is easy to make a connection between &quot;cover, shield&quot; and &quot;umbrella, parasol&quot; because umbrellas/parasols are used too shield oneself from the rain or sun.  In fact, &quot;para&quot; in &quot;parasol&quot; or &quot;parapluie&quot; (French for umbrella) means &quot;protecting against&quot;.