Generally those would be my sentiments, too, mab - but in the case of clipping cuts, there is likely to be dirt on the clippers and hence in the cut, so it's one time it's maybe excusable to use antibiotic spray. Having said which, in our case we'll have two contract shearers powering through the flock, and it's all a bit fast and furious - if you're just doing your own sheep at your own pace, you've got time to clean any wound out properly, in which case antiseptic spray would be fine.