A plan to crack down on the post-midnight finishes which have made a hash of the Tour tennis schedules might harbour a “get-out” clause.

The ATP and WTA – some suggest the announcement foreshadows a future merger of the Tours – dropped the new guidelines on Wednesday with four days to go before the start of the Australian Open.

That major is notorious for late-night matches, some of which have started near midnight; and Melbourne Park heads the Hall of Shame after Lleyton Hewitt beat Marcos Baghdatis in a 2008 third-round epic which did not end until past 4:40 a.m.

Under the new regime, no matches can take to the court after 11:30 p.m., with a maximum of five per day scheduled from an 11 a.m. start.

Evening sessions – recommended start time 6:30 p.m. – should be limited to two per night.

But the rules come with a sting in the tail: 

They can all be overruled by the onsite tournament supervisor, a scenario which it has been suggested will end up becoming the de facto fallback.

Witching-hour finishes have also come to pass at last week’s United Cup in Sydney,with closing days often ending around 2 a.m. – well after the day’s end for public transports, relied on by thousands of fans to carry them the 20 kms back into the city from the distant Olympic precinct.