THEY'RE collecting USING police officers as a way to trick you out of money. They donate very little to what they're collecting for with maybe three cents going on every dollar. In truth, firefighters, and police hate these guys because they're competition for their legitimate charities, often losing out on donations on the count of these thieves. If you're going to donate to hero charities, donate directly, not over the phone.
I don't answer unknown numbers. However, I was expecting a call from a family member and just glimpsed the first three digits "512" which I took to be the Austin area code. Unfortunately it was the prefix for a local number (possibly spoofed). The person began a long speech that was not loud enough for me to understand. He did not pause when I tried to ask who he was and what he was calling about. I just hung up. Now I see that this number is connected with raising funds for a bogus police charity. My wife once made a donation to an organization something like State Troopers Association. That operation was identified by the Texas Attorney General as being a scam rather than a real charity. Apparently they are back in business again.