Opening Bottles on Shabbat

Hello, It is known that the poskim disagree wether it is permitted to open bottles with plastic caps on Shabbat. Is there an opinion that this is prohibited by the Torah? And if so, is it considered a 'doubt of a Torah prohibition' and therefore one should need to be stringent?And if it is indeed considered a 'doubt of a Torah prohibition', would it be correct to say that one should not ask another to open it, since it is against the Halacha, as it is also forbidden for him to open it? And should one be concerned about the prohibition of "Not to place a stumbling block before a blind person" when handing a closed bottle for another to open for him?Thank you very much.

 Shalom Rav,  

 According to those who prohibit - it is a Torah prohibition.  

 For most people, this dispute should be considered a 'doubt of a Torah prohibition'.  

 However, one who follows a particular Posek in all matters, and he is Posek that it is permitted to open such bottles, may act according to this lenient opinion, and it would not even be considered a doubt for him.  

 There is also no prohibition of "...before a blind person" to ask someone who holds it is permitted by Halacha (-as above), since it is permitted for him to do so. 

 However, there is a question whether it is permitted to ask him to do it for you, since the asking is done by the sender, and it is forbidden for him open the bottle, as for him it is a 'doubt of a Torah' prohibition. 

See in detail about this in Azmera Leshimcha 124, 126.