How would one get four air horns past security at the British Library if you had to take them in your bag for a performance…

How would one get four air horns past security at the British Library if you had to take them in your bag for a performance trial run later that night? Asking for a friend.

— Jennifer Lucy Allan (@Jenn1fer_A) June 19, 2018

(via http://twitter.com/Jenn1fer_A/status/1009009400395247618)