How to summon anyone, anytime

I believe there is a Universal Law of Post-It Recall.

In the event you don’t find someone at their desk, the natural thing
to do is start leaving a post-it for them.

Invariably, this involves scrabbling around for such items and begging
nearby desks for a pen.

Of course, the moment you finish your note, the person magically
appears, rendering your writing effort redundant.

I’ve often thought that this magical power could be put to good use.
Someone should pop round to Lord Lucan’s house and start writing him a
post-it.