This might be a foolish question, but I was under the impression that if you had a strong pin/password and an encrypted device, there wasn't much they could do

This might be a foolish question, but I was under the impression that if you had a strong pin/password and an encrypted device, there wasn't much they could do to get the data off the device, no? Won't modern phones (I have an Android) not allow you to see any data unless the device is unlocked? I know when I plug my device into the computer, it will only be in charge mode unless I unlock it and then switch to file transfer mode. Do the authorities have ways around that? Also important to note - the encryption would have to apply to any external expansion SD cards or else they can just remove the card and copy the data.