Doesn't anyone know what 150' means on the lake?

[KDL]

Last weekend we were idling along at no wake speed when a boat approaches us from the left and continues to cross right in front of us forcing us to stop. As he goes by he says he thought we were going to turn left. Really??? He had no clue he broke the 150' and the right of way rules. This would be a good week to stay away from the lake.