I agree, I think that there has to be something said about this practice (if you can call it that).
Sure, I'm not against livening up sections of an installation where they have been finished, but where I draw the line is where people could be injured or killed by the actions/inactions of a bad worker.
I also agree with John (renosteinke), where the guy that is on site, should know what the H*ll he is doing.
He is after all the most competent person with respect to Electricity, he should at least act like it!!.