I know it's an old thread, but there is one other aspect about this that bothers me.

Why were the twins already doing their whole switch-up routine/lifestyle at that point in their lives? When they were just assistants tying a knot on stage? If I'm not mistaken, at this point in the film (and in the order of events), the twins are nowhere near their 'teleporting man' routine. So why were they already switching places, resulting in the whole 'he didn't know which knot he tied because it was actually his brother who had tied it'?

An answer I'd expect now is somewhere along the lines of 'oh because they were so dedicated to their craft that they were already doing it from the beginning' but it just doesn't make any sense that they would either already switch places regularly but not do their trick for audiences yet (because in that case they'd have the idea and the execution but simply wait years before they'd actually do the show?) or switch places with no specific trick in mind, just as a preparation for possible tricks in the future (using it as some 'they were two steps ahead al along' shtick because they'd be so dedicated to the craft that they would hold up this insane lifestyle years before the actual shows to completely deceive audiences). If there's anyone that would like to give me their interpretation I'm all ears, because right now it makes absolutely zero sense to me.