While I’m not a shop owner, I’ve wondered this same thing. As a retail shop, payments come into your node, pushing the liquidity one way. If you periodically move to another node or to an on-chain wallet, would that not balance the channel? Understand, I’m asking here and only theorize this works. I’m an amateur node runner so I could be completely off base. I still get confused about remote and local balances😂🙃😂
Example-
Retailer Node A- receives funds pushing channels to one sided eventually have no liquidity..to get the liquidity, push funds from retail node to Node B (The Bank Node)