Yes, I was aware of the technique of reversing a lens in front of/in place of the existing lens, but never tried it myself. NB: to anyone who wants to try this you will need the additional lens to be one with an "Aperture Ring" so that you can adjust the aperture on that lens (otherwise it will always be wide open! ) and many/most modern lenses don't have one = old is good for this sort of work!
PS: The camera is a Canon A650IS, and I'm not sure if the chap knows this but the "silver" ring around the lens and a little button just below and to one side of that (and which you can't see in the shots in the linked thread) mean that if you push the button and twist the ring, then the ring can be detached. It can then be replaced by an adapter for W/A & Telephoto conversion lenses.
OTOH, the front of the adapter has a (probably 58mm ) female filter thread to which you can attach anything with a 58mm male thread = much easier conversion than bodging it together with tape or whatever!
(I have an A720IS - and that's the same, but I use the adapter to add a lenshood because the camera lens itself has no filter thread!)