>>1i personally choose to tip more than not because more than not the person that's serving / waiting on me earns it. it's not very hard to do either, just be polite, courteous, and to the point.
illegal not to tip? absolutely not. what should be illegal is allowing companies to pay the abhorrent rates per hour that they get away with, the very root of this whole "tipping culture" problem.
there's no reason a fortune 100 company should get away with paying their serving staff well under a collective $5/hour because "well you don't report tips!"
we're the consumers, our job is to pay for services rendered. as an employer it's your job to pay your employees a PROPER rate for their services rendered. it's that fucking easy.
tl;dr - tipping should be voluntary. paying a LIVABLE WAGE TO EMPLOYEES should be mandatory.