B.C. teachers are planning to wear black today to mark the 10th anniversary of two pieces of legislation that have been in dispute for a decade.

Union leaders are warning teachers that wearing black and sporting political buttons could lead to discipline, but said there may be safety in numbers.

The Black Friday protest marks 10 years since the Liberal government passed Bills 27 and 28, which eliminated the ability of the B.C. Teachers' Federation to bargain over class size, class composition and specialistteacher ratios.