It doesn't even have to be "codified" or list every conceivable possibility.
I'm sure every supplement has language similar to the Central Region.
ARTICLE 17—DISCHARGE OR SUSPENSIONS
"The Employer shall not discharge nor suspend any employee without just cause. No employee shall be suspended or discharged without first being given (1) warning letter of a complaint and also be given a local level hearing except for the following offenses"
Do you know the article and languege giving them authority to write you up for it?
There is no progressive discipline, or really and disciplinary recourse for the company if you dont take it. (Nma, plus NE sup). They failed to negotiate discipline in the contract (just like absenteeism.) The law says they must provide you with the oppritunity. However, even if they force you to work through lunch, dot law says 8hr shift, you must take a 30min (minimum) unpaid break/lunch.
They can not bypass law. Take at least 30 min everyday, but really TAKE YOUR FULL LUNCH DURING THE DAY.