I just heard a shiur regarding this.
Simply, there is a concept in Halacha called Shaas HaDechak, and we allow certain things for “B’Dieved”. That does not allow someone else who does not have the B’Dieved to go ahead and use the heter!
Similarly, if you hold opening a bottle cap on shabbos is a melacha, if someone else opens it, that is as far as you are concerned that is Melecha. Whether you can use it or not depends if you define the doer as a shoggeg or Maizid, ask your LOR (See SA OHC 318).