When firearms are found at a checkpoint, the TSA calls local police who determine whether the passenger should be arrested, ticketed or have their gun returned.
The Hackney Weekend (23 and 24 June) will be the biggest free ticketed music event in the UK this year, featuring some of the biggest acts on the planet and all just a shot put throw from the Olympic venues.
The council said the concert at Custom House Square was a non-ticketed event and entry would be on a first come, first served basis with gates opening at 12:00 GMT.