The new security measure targets accounts used by third party trackers and prevents them from seeing rare spawns in the scanned area. In term, spoofers who use trackers to snipe rare Pokémon can not see them. Although this change doesn’t stop spoofing completely, it discourages spoofers from taking action.
This is how the new security measure looks like in action — both accounts are at the exact same coordinates, at the same time.
Image courtesy of PoGO Dev discord:
This is a bandaid fix and it targets only accounts that were previously detected and flagged as malicious. Several trackers have already defeated the new security measure by creating fresh new accounts.
Community reactions say that this measure hurts also legitimate players that occasionally use tracking apps. Although using map trackers is against the in-game ToS, our recent Twitter poll showed that 81% of participants are OK with that:
We’re quite curious about one question. Here it goes: what’s your attitude towards trackers (tracking/scanning apps)?
— Pokémon GO Hub (@PokemonGOHubNet) May 7, 2017
Rumors in the development community show that the majority of flagged accounts are bot accounts, spread across various APIs and services.