A new Bill before Parliament proposes reducing the number of times a temporary alcohol licence can be granted for one-off events at a single location from 12 per year to five. The number of people allowed at fetes and similar events would also be capped at 500.
However, the proposals would make it easier to get temporary licences as they will eliminate the need for heads to apply to magistrates' courts. Instead they will merely have to get police approval.
The Licensing Bill is at committee stage in the House of Lords. It aims to reform antiquated drinking laws, reduce drunkenness and disorder, and protect children.
But restrictions on events could hit large secondaries with money-spinning beer tents at summer fetes. Schools wanting to run more than five events a year where alcohol is sold will have to apply for permanent licences, effectively turning heads into landlords.
Neil Shestopal, a partner at Barnett Alexander Conway Ingram solicitors, said: "It's easier to apply. The police will check out the applicant and provided everything is OK it will go through on the nod and you won't have heads having to troop up in front of magistrates. What schools have got to do is (think about) where events are held, in view of the limit of five."
David Hart, general secretary of the National Association of Head Teachers, said: "As more schools follow the Government's line on extended schools, some may want to apply for full licences. But I don't see why schools should be forced to apply for a full licence just because they want to put on more than five functions a year."
There are also concerns that a requirement that all licensees are criminally checked could add to the workload of the Criminal Records Bureau just as it is handling its annual bulge in applications from newly-appointed staff and trainees next autumn.