There’s a mystery hacker who’s been changing the wording on digital traffic signs in the city. Is it amusing? Or dangerous behavior that should be stopped?

not an isolated incident:

— Eli Wirtschafter (@RadioEli) September 2, 2019

This happened Tuesday. Who are the mysterious hackers?

— Berkeleyside (@berkeleyside) September 4, 2019

Ok #maketransitfree hack on California St in Berkeley today

— phyllis orrick (@orrickle) September 3, 2019

A hacked sign at Lincoln and California. Photo: Citizen reporter

I noticed it on Friday evening around midnight

— John Vantine (@w00t) September 10, 2019

Editors’ note: This article was updated as readers sent in more hacked signs.

Frances Dinkelspiel, Berkeleyside and CItyside co-founder, is a journalist and author. Her first book, Towers of Gold: How One Jewish Immigrant Named Isaias Hellman Created California, published in November...