The Collaborative International Dictionary
Blanket mortgage \Blanket mortgage\ or Blanket policy \Blanket policy\ . One that covers a group or class of things or properties instead of one or more things mentioned individually, as where a mortgage secures various debts as a group, or subjects a group or class of different pieces of property to one general lien.
Wikipedia
Blanket policy is a policy which behaves similarly to a variety of things. Based on Webster's Dictionary it "covers a group or class of things or properties instead of one or more things mentioned individually, as where a mortgage secures various debts as a group, or subjects a group or class of different pieces of property to one general lien."
Usage examples of "blanket policy".
The blanket policy of confiscating all weapons that had been enacted after 9/11 had been relaxed somewhat, although without her badge it was not that easy.