Trying to follow every new rule, law or ordinance proposed by government is nearly an impossible task, even for the most careful watchdogs of government. Sometimes new restrictions or special interest giveaways occur and no one realizes it until it is too late.

A perfect example of this is the current debate in the City of Phoenix over the new concession contracts that will be awarded for the renovations to terminal three at Sky Harbor Airport. The bid process itself is crafted by an obscure subcommittee that is only followed by politically connected special interests seeking to acquire these lucrative contracts, including the powerful labor unions that control city politics.

Last week, during a debate over the point system that would be used to evaluate proposed construction bids, language was added that would require contractors to disclose whether they have an agreement in place that prohibits labor unions from striking, picketing or engaging in similar economic actions. The purpose of the is language is simple: unions want to know which private sector employers are hostile to labor so that they can be blackballed from securing contracts from the city.

The union assault on employment agreements and government contracts isn’t a new tactic. The Obama administration’s (likely illegal) rule adopted last year that would have stripped employers of federal contracts for mere allegations of violations of federal labor law was similarly conceived to give unions leverage over companies seeking federal contracts. Fortunately for contractors and taxpayers, the rule was stopped in court and repealed by congress before it could take effect.

If City Hall is successful with adding this requirement to airport concession contracts, it will only be a matter of time before this stipulation is added to all city agreements in the future. Phoenix residents would be wise to oppose; as it will only empower unions, harm private employers and drive up costs for taxpayers.