carpet, lend, borrow, make excuses, spread out
藉 centers on using something as a base or intermediary: spreading a carpet to sit on, borrowing or lending through an intermediary, or making excuses as a pretext. The meanings share the idea of placing something underneath or between as a support or justification.
藉 combines 艹 (grass) with 耤, which historically relates to plowing and likely contributes the sound. The idea of grass spread on the ground connects to carpet and spreading out, while the borrowing and excuse senses are extended uses.
Grass 艹 spread over the ground 耤 becomes a natural carpet. From there, imagine using that grass mat as an excuse to borrow something: 'I need to lend you this, but first let me spread out my grass carpet.'
For シャ, picture a shaggy grass carpet spread out on the floor: shag -> シャ, and the shaggy carpet is the perfect base for making excuses.
disorder; confusion
running amok; committing an outrage; rampageous behavior
relying on; depending on
glasses and plates being scattered about after a party or banquet; articles lying about in a jumble
rioter; ruffian
running amok; committing violence on; in utter disorder
pretence; pretense