Heck, Spirit has been charging for sodas for at least 6 months, and their business model has not been adversely affected.
Are you sure about that? The following is an excerpt from a communication from the Spirit ALPA rep to all Spirit pilots...
"Greetings fellow Spirit pilots,
At 1744 EDT Friday evening our Vice President of Operations, Jeff Carlson, sent facsimile copies of three certified letters to ALPA President Capt. John Prater. These letters were notices pursuant to the Worker Adjustment and Retraining Notification Act (WARN).
Spirit Airlines gave the minimum required legal notice of potential base closings in LGA and SJU, and of a potential reduction in base size in FLL. Capt. Creed, upon hearing of the notices, spoke directly with Ben Baldanza. Ben indicated Spirit would be finalizing decisions concerning these bases in the next week, and merely wanted to have the legal notification in play for that eventuality.
Under the WARN Act the Company is required to provide an accurate number of those employees who could be affected by these types of decisions.
Spirit has indicated 242 pilots are exposed to displacement or furlough. We hope their plan includes the growth of other bases but it's hard to imagine the economic benefit of such realignment in these times of cost control."
Another post in the same thread said "Spirit may lay off or move up to 60 percent of its flight attendants and 45 percent of its pilots in an effort to cut costs and deal with soaring fuel prices, according to letters released Tuesday by union leaders."
Granted, you can't say that charging for sodas caused this, but you also can not say that is has had no effect.