"We follow up on all calls of that nature,'' said local police sergeant Mike Brooklands, who added the caller wasn't someone who was at the meeting.
Armstrong was charged with drink-driving for the fourth time.
Defence counsel Donald Dickson accepted it was Armstrong's fourth conviction but said his last one was more than seven years ago.
But Judge Tony Couch was concerned at the high reading and called for reports before he could be sentenced.
Mr Dickson asked that Armstrong be allowed to drive before he was sentenced so he could keep his job but the judge said he had had "lost his privilege of driving by his actions''.
Armstrong was remanded on bail for sentencing on July 12.