The AT&T logo is seen on the safety helmet of advance-line technician. The sticker would not be seen from this angle.
A pro-union sticker that read WTF is sparking a controversy for AT&T managers and their workers this week.
The stickers refer to a labor dispute between AT&T and technicians, who have been working without a contract for about a week.
The technicians wanted to wear the sticker as a form of protest, but anyone who refused to take the sticker off was told to go home from work both Monday and Tuesday.
The union claims WTF stands for "Where's The Fairness?" but it is well known for another phrase that includes a expletive.
Because many of the union members opted to go home instead of removing the sticker, customers were left waiting for a home visit that never came. AT&T did not give an estimated number of customers who were impacted by the sticker controversy.
Communications Workers of American spokeswoman Libby Sayre told the San Mateo Times that employees who wore the badges were turned away from offices in San Mateo, San Jose, Sacramento and Reno.
The union headquarters in San Jose had a stack of stickers and workers there had no apologies for the three letters.
AT&T told KTVU its company policy requires appropriate dress for employees. "We don't believe such a sticker or button is appropriate in our customers' homes and businesses," AT&T said in the statement.