I have no idea. Sorry. If it works, great. But, it should be sending your data row in details and you should be able to work with your own ID to find your data and work with it as you need to. Thing is, the row index will change, if the user reorders or filters (if you have those features in use) the table. That’s why you should work with your own data id field and not the row index of the table.
When tickStrategy is leaf, only leaves that are ticked are returned. In your case, usuarios is not a leaf, since it has children.
If you want to have the branch in ticked array as well, you have to stick with strict mode, and make an event handler to automatically tick/untick children when parent is ticked.