When a family installed a blue light outside their home to mark Autism Awareness Month, they never expected it to bring a backlash from one of their neighbors.

Julie and Matthew Riccardi say that an anonymous note was left in the mailbox of their Charlotte, N.C. home criticizing the blue-colored light bulb they put outside their garage to promote autism awareness.

“Seriously? Purple, blue lights on the garage? Mom always said there is one bad apple in the bunch,” read the note, which also indicated that the area homeowners’ association would likely have a problem with the lighting color.

Contrary to the mystery critic’s prediction, however, the HOA was nothing but supportive of the Riccardis and their 10-year-old son, Deacon, who has autism. In fact, almost a dozen of the family’s neighbors opted to swap out their light bulbs for blue ones as well, reports WCNC, the Charlotte NBC affiliate.