My question is this- has anyone subbed work and had probs with the subbies trying to 'poach' the work 'you' were doing, or any probs in general with sub contracting.
You may as well ask do bears do a poop in the woods,
We once hired a subbie for a largish job and he went straight in and under cut us with the corrupt building manager,
(this guy charged tradesmen to use the lift).
It did not go down well and we made our thoughts clear to him in no uncertain terms, but hey its a gamble and it does not mean they are all like that, we have had some great subbies work for us as well.
On insurance your normal public liability should be good anough and do not employ any subbie who does not have up to date cover for themselves, take a copy and keep it on file.