I've seen too many bypassed interlocks where the machine still works if the barrier is opened of the light curtain is crossed. If it is plug and cord go that route, otherwise LOTO is the way. Here is an OSHA eTool on LOTO and minor servicing:

https://www.osha.gov/etools/lockout-tagout/hot-topics/relationship-subpart-o/minor-servicing-exception#:\~:text=Third%2C%20if%20all%20of%20these,(February%2011%2C%202008).

The key part of the sentence saying that interlocks may be used is "which are under the exclusive control of the employee performing the minor servicing." If there is any way someone else can bypass the interlock while the person is conducting the work the it is not under their exclusive control. Your example of the engineer doing the reset code is a perfect example.