Adding strangers to your security circle will have consequences in the future. Add the people you KNOW and TRUST to your security circle.
5 trusted members in your security will beefed up and secure the currency by building a global trust graph that prevents bad actors from executing fradulent transactions on Pi's ledger.
Pi’s consensus algorithm requirement (security circles) make it easy to detect fake accounts. Fake accounts will not have enough real people pointing at them via security circles. At best, fake accounts would be pointing at each other with very few incoming pointers from the rest of the network. This anomaly is easy to detect with computer algorithms.
Adding the people you know and trust to your security circle means you've vouched them as real human and as people that cannot executive fradulent transactions on Pi's ledger.