The tip line, 1-877-613-2137, is a toll-free number. As a tip line they probably do not have pay phones blocked.
All major phone carriers will charge them around 25 to 50 cents per call that originates from a pay phone, in addition to the per-minute rates.
Also, pay phones are generally anonymous. So, if a few thousand people decide to call dozens of times to give them some helpful tips, this would cost them tens of thousands of dollars.
Hypothetically, of course.
Of course. ;)
or leave cards in every box you pass, just straight advertising “this is a DOJ flag line against Sherrif Joe, the illegal-stopping Sherrif. phone them”