OK, I do this too,when I am in surgery ( or taking a day off). My office staff knows full well what my log in is, they can write release letters, prescriptions or what-ever. This was always the case with the paper office, there were pre-signed prescriptions, they could call in an Rx, etc. There is more than one signature stamper in the office, they could stamp my signature onto a form 1040 if they wanted. It is ( and was ) necessary to have trust in your office staff.
What we are currently doing is trying to be more transparent/ honest and printing up the release or order under their log-in with their name and they write in beneath their signature "for Dr. Lehmann". so far this has not produced any problems and is an honest representation of delegation of authority. They then forward it to me for a sign off. I don't know what we will do when every thing is truely electronic, but that is not here now, and these things are still on paper going out of the office.