Laura Smallwood died after being hit by a costume with a large wooden circle weighing more than 50lbs (23kg) and worn by a masked male dancer during a traditional Cornish May Day parade in Padstow in 2019.
An inquest into the death of a nurse, who was hit in the neck by a horse costume during a parade, has heard the festival needs to become better organised to reduce the risk of further tragedies.
Cornwall's senior coroner, Andrew Cox, ruled Laura Smallwood's death was accidental, but said he would write to the government outlining his concerns over the management of large events
Mrs Smallwood, 34, died after she was struck by a horse costume with a large wooden circle weighing more than 50lbs (23kg) during a traditional Cornish May Day parade.
The costume was worn by a masked male dancer making his way through Padstow, north Cornwall, in the 2019 Obby Oss festival.
The paediatric nurse died in hospital three days later.
The centuries-old event attracts up to 20,000 people each year, and Mr Cox said the two Osses which parade through the town posed a risk to the public.
"The packed nature of the streets, the fact people have inevitably been drinking alcohol and will not be paying full attention to what is happening around them, means the risk of inadvertent, unintended contact between the Oss and a member of the public is obvious," he said.
The inquest in Truro heard that each Oss has a separate organising committee.
Mr Cox said contact between the committees and other agencies up to 2018 was "limited and far from ideal".
He also said: "I find it frankly surprising for an event of this size there is still no single event organiser who is involved with the local safety advisory group, the police and other external agencies."
Mr Cox added: "It cannot be right, in my view, to have an event of that size with, for example, no arrangements in place for reuniting lost children with their parents or a community first responder being unable to gain access to an emergency because of a padlocked gate.
Noting things had improved somewhat before Ms Smallwood's death, he said it was "reassuring to hear there has been a recognition of the need to move with the times and to do more".
He had no wish, he said, to promote a nanny state, but said the lack of a single event organiser meant "sensible planning and risk reduction is inevitably compromised".
The inquest heard Mrs Smallwood, from Padstow, collapsed after being struck by the Oss.
A post-mortem examination found she had suffered an earlier head injury around 10 days before she died and had also been involved in a minor scuffle with a woman at the parade.
Mr Cox said Mrs Smallwood had not complained of the earlier injury and "laughed off" the confrontation.
The coroner said his preventing future deaths report would highlight to the government his concerns about events not being compelled to have an organiser and also the police's lack of powers to stop them.