All the examples are true with any application. CCTV, CATV, Access Control.

1. Multiple contractors for the same application creates many conflicts. If one person installs the software, one cabling and one cameras and each have a separate maintenance contract. If the contractor doing the software installs an update and a day later there is a problem with a camera. Whose fault is the failure. The camera contractor is going to blame the software installer and the software installer is going to blame cameras. This is true for access control also.
2. What if the customer wants to add a device to the existing system? The customer has to negotiate with multiple vendors. The customer has to work out schedules for the different contractors to do their work.
3. What if the customer wants to move a device? Two or three different contractors have to be contacted. One to move the device and one to make the changes in software.
4. Who has passwords?
5. What if a camera is fuzzy or has some other problem that is corrected through the software?  Who does the customer call? A lot of focus problems are corrected through the software. Does this mean that anytime something is done both contractors have to be onsite? If a camera is fuzzy the hardware contractor is going to blame the software contactor for doing something to the camera.