Signing Bonuses: Indentured Servitude of the Engineering World

Is this common? I would never accept this. The 10k shackles guy could still pursue new employment with a 10k+ signing bonus (without strings this time) to pay off the first, or take his chances and leave to see what a judge will say.

Edit: relevant article with some good advice (pro-rated, pay off over time, negotiate) so I guess it's not uncommon, just a bad deal. http://www.bryankuhnlaw.com/blog/2014/04/signing-bonuses.sht...