Actually, no they don't. Many a frustrated pilot have been hired by a company that currently had fast upgrades and couldn't understand what happened as they waited years and years to do so. Anyone hired by PSA in the last 6 months will likely get to know this feeling well.

When I was hired by Eagle, the upgrade had gone from two years to 6 years and growing. It had peaked at 10 years, 10 years to upgrade but it took me 6 1/2 years. It has currently gone from that to almost 8 years and the current junior Captain is a Oct 2007 hire. 220 upgrades next year will make it a late 2008 hire. After them it was a hiring gap so it will jump to a 2010 hire.

You may like to speculate that they will stop the flow but it is a contractual provision just like any other provision. You might as well say, "Don't go to RAH, they cannot afford to pay their $40 so your paycheck will bounce." "Don't go to SkyWest, they don't have a contract and they can do whatever they want"