Defending champion Ding Junhui has refused to rule out the possibility of withdrawing from the UK Championship in Milton Keynes if spectators are allowed back into the venue.
Tournament officials are believed to be exploring the possibility of welcoming some fans for the final stages of the tournament next week, in line with the latest government rules.
But after beating Jamie Curtis-Barrett 6-1 in the first round, Ding said: "It's too risky.
"If they put some crowd in there I will think about that (withdrawing), and other options."
Matthew Selt knocked in a record-equalling five centuries in his 6-0 whitewash of Morocco's Amine Amiri, with Judd Trump and Fergal O'Brien the only other men to have preciously managed the feat.
Jack Lisowski also progressed to the second round with ease after inflicting a 6-2 defeat on Farakh Ajaib.
However, Ken Doherty was defeated by Ning Lu of China by six frames to four, while Cork teenager Aaron Hill lost 6-3 to Norway's Kurt Maflin.