Actually Paul, I don't know that and neither do you.

Whether the US or anyone else civilian casualties are largely dependent on the type of warfare. Guerrilla war, especially where the insurgents use the civilians as cover are especially difficult. However, as shown in Libya tipping the balance by aiming at military hardware lead to very few civilian deaths.

Considering nearly 100 civilians are dying a day, this is a life saving measure.

I think it would be wise to stay out of the conflict in Syria. It would be impossible to distinguish between the good guys and the bad guys. They all seem potentially bad and the reported 200 Australians fighting with the rebels are not going to bring any good intentions back to Australia on their return.
Maybe the drones would be better employed as a detriment to the boatloads of the unstable and least desirable that this conflict will send our way. Keating and Fraser accepted some 75,000 displaced Lebanese from refugee camps in Syria during the 1970’s. These people seeded the problems faced in South West Sydney today.