Is signing a pdf file electronically with Preview safe? I would like to sign PDF forms using Preview but I am hesitant that the signature can be copied by the receiving party. Has it been ensured that it cannot be copied? Of course, I realise that it could be printed and scanned, however the more troublesome, the safer it is.
With photo editors being what they are, it would be trivially easy to cut a signature out of a scanned signed document and put it on any other scanned document in a way that would be nigh-impossible to detect as fraudulent.

Yes, PDF editors would probably be able to snip out your signature. This, of all things, should not concern you.