In the UK they are any bond is un-enforceable in law after the Bosman ruling in football. This made any employer unable to restrict the movement of employees to better and other employment or career changes.
Most companies will try it on and threaten you with legal action, but the chances of them suceeding are almost nil. So you have to sign the agreement in the full knowledge that you may not honour it, or miss out on the benefit of training. Not a good situation IMHO.