I'm not up on the view but it is not unusual for all vehicles to have small voltage drains ( parasitic drains?) and many do want to disconnect the battery. One of the easy methods I have used on boats and RV are pretty cheap and easy to install and use if the battery is easy to access.
These are both types which I have used :
This one, you put on the post and unscrew the green knob to cut power.
This is somewhat more secure but can take more thought to find where to put it. On this, you turn the big key to cut power,remove the key and nobody can turn it back on .
They don't have to come from Harbor Freight but just where I found pictures and they are plenty sturdy and cheap--- if the situation is right. Much easier than removing cables, etc.