Paolo,
A quick examination of pieces in my collection showed that the following editions did not use brackets for the pedal, rather Ped. * was used.
Paragon, Fryderyka Chopin Institute, Breitkopf & Hartel, and Edwin F. Kalmus.
Mark
Hi Mark,
this is expected. The pedal bracket is a relatively recent practice in music engraving, and the "/\" is even newer (I suspect this last one is a standard "de facto" after Finale or Sibelius).
Then a research is not easy, because it has to focus on the last, let's say, 20 years.
I don't know exactly the state of the art of it. It could be that it is not so wanted if you use only one pedal (but IMHO it would be bad to see as well, because all the other spanners normally have a cautionary string)
But as soon as you use different pedals (sostenuto or una corda), regardless if you use one or multiple spanners at the same time, I would really be surprised to see no cautionary.
Best,
P