Some bouncers have been demanding people hand over their smartphones so they can check Facebook accounts, Newsbeat has been told.
It's claimed that it is to make sure the person is who they say they are and isn't using fake identification.
It happened to Charlotte Neal, 20, who said there had been a few times where bouncers had asked to see her phone.
Charlotte said bouncers had checked that her Facebook name matched her driving licence.
"I kind of just logged onto it [Facebook] and showed him the screen and then he didn't question it any further," explained Charlotte.
"When it happened the first time I didn't really think anything of it.
"Then I thought, 'Hang on, is this really how you're supposed to check how old I am?' But I was out and I wanted to get in the club so I just agreed."
Charlotte, who's from Southampton, said she often gets asked for identification.
"I just think great, 'Here we go again, they're going to question me, they're going to ask my date of birth, my star sign, and they're going to ask to see a different ID or something.'
"I do understand why they want to verify it, but at the same time if you've got an ID in front of you, why isn't that good enough?"
It wasn't just Charlotte this has happened to, other Newsbeat listeners wrote on Facebook and said it had happened to them, one person said it happened all the time where they live in Northern Ireland.
Nick Pickles, from the campaign group Big Brother Watch, said he was against the idea of checking Facebook accounts.
"Not only is it ridiculous from a security point of view, it's an affront to the basic rights of people to be able to live their lives in private," he said.
"If the problem is that people haven't got good enough quality IDs, then let's make sure they do have good enough quality IDs.
"This shouldn't be an excuse for nightclubs to snoop and pry into people's private lives."
Some door staff have contacted Newsbeat to defend the idea of checking Facebook profiles.
They say the consequences of letting someone in who's underage are serious, with the potential for a large fine.
"I believe the fine for letting in an underage person is £5,000," said a doorman from Worthing.
"Why is it so wrong for people to have to prove the ID is actually them? If you're not doing anything wrong you shouldn't have a problem."
Chris, a bar owner from Folkestone, told Newsbeat that convincing fake ID was easy to get - and often very hard for door staff to spot.
"Checking phones with consent is at least a more certain way," he said.
However, Paul Martin-Beades, the director of Akira Training, which trains about 250 door staff a year, said checking Facebook accounts was unacceptable.
He said all staff approved by the Security Industry Authority (SIA) are taught about the law and human rights and would know it was wrong.
"Only the people involved can say why they do this but they would never have been taught to do it."