Digital evidence is IMO a different matter than physical evidence.
The threshold for implanting fake digital evidence is very low. You need fewer people, you can cover your traces easily... 
To break-in and install cameras you need to find a suitable time where the suspect is away for a long time. And you can&#x27;t always break-in to the house and change things, you won&#x27;t be permitted.
The monitoring of the use of these trojans is the most important problem.
With a trojan horse you have access to the computer 24&#x2F;7 and you can do whatever you want. 
Of course you could argue that police could also plant fake physical evidence, but that&#x27;s a lot harder to do and you need more people. (more witnesses)
There is a thin line seperating a state of law from a police state.