Many of us tend to be very trusting with regard to Kashrut. But, there are numerous exhortations within Shas and Poskim to Verify whenever Possible.
I recently ran across this re: Nikkur Haggid. While it is true that "Rov HaMetzuyin Eitzel Nikkur Mumchim Heim" nevertheless it is always best to verify, EG when the original M'nakker is absent.
Rema Y"D 65:13
Ba'er Hetev 65:6 quoting Reshal
Bei'ur HaGra 65:32 citing Siman 1 "d'ein som'chin on Harov bid'leita kaman"