It is important not to make generalizations because every incident is different, but several accounts pointed to the betrayal by Jews against the Poles that were saving them.
This information surely impacted whether Poles did offer help to Jews knowing what may be in store for them if the Jews were caught.
Firsthand accounts from that era do provide information that in fact, these actions did occur and they were not uncommon.
They became so common in fact that orders by the Home Army were made not to help Jews because of the amount of Polish losses that were being inflicted.
Please read the last picture's quote to understand the seriousness of this problem and how this was affecting the Poles.