Internal policies should be developed to lockdown the special equipment, and (at least) create a list that denotes miscellaneous cables that are essential for that gear, and note where it is supposed to be located and a sign out space to be used when the equipment is moved.
Since these setups are only done once in a while, the person previously trained may be somewhere else. In a similar vein, variations that finally made the equipment work the last time were left undocumented.
A manual of these technical special setups should be created, with a checklist of each setup as it is added, with a sign-off space for people to initial as they are trained on each. Overall training is often difficult to schedule, but setting date certain times in advance, such as Spring Training and Fall Training has been a successful way to deal with the issue.
Please use this thread to note other problems – or to shine more light on these few mentioned – and any successful actions that cinema techs and management have used to handle personnel training for the different variations of non-cinema presentations.