Last night at the Jenison league they did go over the rules about parents and coaches calling instructions from the sidelines.
To explain: Teams are allowed to have up to three members standing at the field during play and one of the members can be a coach but they are not allowed to drive or touch anything. An additional person coaching from the sidelines is considered as “an acting team member”. This person is 1) not at the operators position at the field and 2) may cause the team to exceed their allotted three member limit. Both offenses can be reason for disqualification.
Keep in mind that the intent is to curb the behavior. This is a technicality and most offenses will result in a warning from the officials but there have been teams disqualified because of adult involvement in past seasons which can ruin their chances of success.