Md. Code, Commercial Law § 11–103

It is unlawful for a person to:

(a) Knowingly participate in a discriminatory boycott; or

(b) Knowingly aid or assist any other person in participating in a discriminatory boycott. However, nothing in this subtitle shall make it unlawful for any person who does not otherwise participate or agree to participate in a “discriminatory boycott” merely to handle or ship the goods of a person who may be in violation of this subtitle.