I worked at a place where the developers were all underpaid (due to it being a 'startup', and there being the promise of more down the line...). When annual reviews came round (after the company posted strong profits), nobody got their raises, and promptly handed in their notices. In an attempt to scramble to save the company, management agreed to bring them up to much more reasonable salaries, but could only do so with a promotion - since the payrise was too big for the board to approve without one. So everyone in the company became a senior developer at once...