According to Hacham Ovadia Yosef there is a Halacha of Safek Berachot Lehakel meaning that in any case that there is one (or two I can't remember but it doesn't matter for my example) Posekim that ...
If you know that let's say John Hancock's thrift store's profits go to a church are you allowed to purchase things there? What if you don't where the money goes but are in Safek whether it goes to a ...
The Tur writes (Orah Haim 11) that since in his days they didn't have Techelet they didn't have to be Makpid on the Huliot (the Rambam doesn't agree). Therefor the Posekim hold (Rosh, Tur, SH"A etc.) ...
The Gemara in Shabbos says that Bibi bar Abaye asks if one can violate a Rabbinic commandment (unsticking a loaf from an oven) to save oneself from being "chayav a chattas". The Gemara says that ...