No encryption no proof
Going a bit conspiracy theory on this.
If the encryption has a back door they will be able to put encrypted things on your device at anytime, and then do an official seize and search and find illegal content. Its encrypted with your password on your encrypted device, so it must be yours. Think of it like the police having a key to your house, going in last month and planting some drugs, then doing a raid finding the drugs. You end up going to prison as you had drugs in your house so you must be a dealer.
Of course it could also be used the other way. As any back door can/will be found and used by others, you could claim things have been added to your encrypted device encrypted with your password without your knowledge and they are not yours. So someone with power, say a politician, gets found with compromising things, say messages ordering illegal things to be done, on their phone they can claim it’s not theirs. It becomes a get out of jail free card for those who can afford the legal team to argue it in court.
I'm not into conspiracy theories, I just work in IT where unless it is impossible for a user to do something they will find a way to do it no matter how strange or unlikely it is, so I think up those things to and then try to make them impossible to do. Don’t create the SQL script to get order details on your website and just run it, as a user will find some way of changing that script to do something else , simple stuff really.