Actually it’s usually closer to 5%, but to avoid consumers getting mad most companies have internal variance limits of less. Still, 2% is pretty tight for manufacturing equipment. Despite the mass prevalence of corporate greed, it does end up being better for most companies overall to be on the slightly heavy end of net weight rather than lower end and most manufacturing guardrails and in line weight checks are calibrated with that in mind.
This is entirely due to the risk of images like this going viral and causing blowback for the company. So, to keep products on average a little heavier, posting things like this is great
An alternative way to view this: if I order three sodas at a fancy restaurant vs three top shelf alcohols, the service is functionally the same but the bill is wildly different. Would you still say I should tip on pure percentage in the latter scenario?