Snooker players are being treated like “lab rats” by allowing spectators into the Crucible Theatre for the World Championship, says Ronnie O’Sullivan.
The tournament, which begins on Friday, will be the first indoor sporting event with crowds, allowing around 300 supporters to attend each session.
Qualifier Anthony Hamilton, who suffers from severe asthma, says it is “ridiculous” and “too early” for fans.
Five-time world champion O’Sullivan said players “all run a bit of a risk”.
A number of sports have already returned behind closed doors but snooker will be the second government-backed pilot event after the Surrey v Middlesex friendly in cricket to be staged in front of fans.
Those that have booked tickets to attend the Sheffield venue will be placed in ‘bubbles’ of up to four people – limited to a maximum of two households – and will be socially distanced from others in the arena.
Temperature checks will not be in place and face masks must be worn around the venue but can be removed once seated inside.
World number 48 Hamilton pulled out of the Tour Championship – the first event that was played on the sport’s return – because of health concerns and called the decision to allow people to take off their masks in the auditorium “a mad thing”.
He added: “Let’s say one person gets ill and dies from the Crucible, that is one person who has died for no reason, just for entertainment.
“I won’t be comfortable in there personally, I don’t know why anybody would be comfortable, we all know it is airborne.”
World Snooker Tour said being designated as the first indoor event in the UK was a “fantastic triumph” and that health and safety was the “highest priority and protection for our fans, players and staff”.
O’Sullivan said: “I defy anybody if they have been keeping their distance from people for four months to say, oh right, now you’ve got to go into a room full of people – unless you have got a death wish, and some people have in many ways and they just don’t care.
“But if you are one of these people that happens to care about your health and are taking it seriously, I totally get how he feels.
“I would feel a bit strange walking in a room with 10 people I don’t know, and I have done. I didn’t feel comfortable.
“So I totally respect where Anthony is coming from, and where other people are coming from – they want crowds in there, they want things back to normal. We have a choice we don’t have to go and play. We all run a bit of a risk.
“I don’t think it’s a risk worth taking. I have the option not to play but I’ve decided to play. Maybe with 5,000 fans I could see it’s a bit of an income you’re going to lose, but 200 fans, is it really?
“Maybe they have to start doing a test on crowds at some point and I’ve heard people say they’re treating the snooker event a little bit like lab rats – you’ve got to start somewhere, start with snooker players.
“Less insurance to pay out for Anthony Hamilton than there is for Lewis Hamilton.”
O’Sullivan says he has had friends die from Covid-19 and has not been within 20ft of his mum who is in the “high risk” category as she had pneumonia last year.
“It’s not until you’ve had people close to you that have gone through it, and know someone who has died,” he said.
“And I’ve had nurses who I have spoken to and they say, ‘People have come in with Covid-19 and they think they are going to be alright and it’s not until they can’t breathe that they say “please don’t let me die”.’
“Grown men and women crying their eyes out because they can’t breathe. It’s only when something like that happens and you hear those stories that you go ‘hold on a minute, this is serious’.
“I don’t think it has been taken seriously enough.”
The opening matches begin at 10:00 BST live across the BBC, with defending champion Judd Trump in action against Tom Ford, while O’Sullivan starts his campaign against Thailand’s Thepchaiya Un-Nooh on Sunday.