Hm.
I’d be careful with people who believe they think outside the box. Usually they just think inside another box. Usually it’s a worse box, too.
In general, if there are 1000 options, I think usually 900 of them don’t work, 97 are the tried and true methods “inside the box”, and there are 3 options that are both original and feasible.
I’d advise anyone to stick with the box unless they have a clear idea with other merits than originality that just happens not to be in there.
Furthermore, if we’re going to use this metaphor, there are many boxes you can think in, perhaps infinitely many. Some boxes are just really beneficial, like a box that delimits all the possible ideas to only those that have a realistic chance of working.
Further reading: The ‘Outside the Box’ Box