How do you prevent data bleed and other cogitations?

You have multiple accounts on your system and they're all accessing their data. How do you limit all data access to the current user's account? Global scopes, policies and guards, additional where clauses, crossed fingers...?

Using code examples and some walk-throughs, let's see how we each tackle the problem currently, discuss the pros and cons of each approach, and see if we can come to any agreement on the best ones. How does a Laravel approach differ from other frameworks?

If you can bring your laptops then great.

See you there ( hopefully :0 )

Venue: I'll see if there is a better option than the Nelson, but let's use that as the err... Backstop!