A $700 fine is small change compared to what it could have cost trainer Jason Coyle for leaving a lead bag off Berry Delicious at Rosehill.

The filly was the $2.90 favourite for Saturday's Alpha Flight Services (1350m) and luckily the 1.6kg mistake was picked up before she raced and won.

Her jockey Winona Costin checked the gear in the mounting enclosure and when the omission was uncovered, Berry Delicious was resaddled and went on to beat Sense and Reason ($9.50) by a neck.

But as Coyle was reminded by chief steward Ray Murrihy, the mistake could have had serious consequences.

If it had not been discovered, Berry Delicious would have been disqualified and punters out of pocket.

"All's well that ends well, but it was a serious blue," Murrihy said.

"It was a mistake that could have cost hundreds of thousands of dollars, if not millions, with the favourite in a Saturday metropolitan race.

"She would have been disqualified if she had come back without the lead bag."

Coyle pleaded guilty and said he could offer no explanation for his error.

"I have no explanation other than I'm a very stressed horse trainer," he said with a laugh.

Berry Delicious will now have a two or three week break and return for the early mares' races in the spring.