errr, nearly correct Herman, but...
Swiss will clear you down to FL170 and ask you to report when you are ready to cancel IFR. By definition, you may only cancel IFR if you are able to maintain VFR.
Once IFR has been acknowledged as cancelled, and if you are able to descend in accordance with VFR, there is nothing to prohibit you from flying below MSA, even if you cannot actually (yet) see the airport. The legality here relates to continuing flight under VFR and has nothing to do with the fact that you may be well below surrounding terrain.
If you are able to maintain VFR all the way down through any hole you may find you have not broken any rules.
If, before descending, and after having cancelled IFR you have reason to think that you may not make it all the way down, Swiss prefer you to let them know that you might just "pop back up" in readiness for your divert.
Too many people make a big deal about Samedan. There is no "white man's magic" associated with landing there - it's just good stick and rudder fun!