Negative, you always address the job symbol, and the engine number, as well as conductor (last name here) when requesting and confirming three-step protection. The engineer will also relay the same whilst applying/removing it.
So no, there is no possibility of or room for error. It’s a failsafe system. Engineers never let you get three staff or go in between unless you have three steps of protection, and it is requested and confirmed properly verbally over the radio. Keep in mind you need at least 5 to 10 years to become an engineer, so by that time you’ve conducted enough to understand what it entails.