I bought 7 Frontier tickets today in about 15 minutes at the airport counter. Very efficient. Saves $23 each on the too-clever Carrier Interface Charge, or $13 off the Discount Den price. Similar to the prices I was paying for Southwest a year ago.
I will fly Southwest when (a) Frontier's schedule or price is unfavorable, and (b) when Southwest is not charging more than Alaska or United or AA. This will mean almost no OAK flights unless Southwest stops gouging OAK customers.
And that is how it should be.. you as a customer pick the best option for you and what you are willing to pay. Vote with your wallet. Folks who want to fly with WN will pay or choose not to pay and fly elsewhere. And Frontier, Spirit are actually good options especially if you take their big seat and pay for some of the upgrades. Blind loyalty to any airline is counterproductive IMO. Pick an airline that best serves you and go with it !