Here is a good reason why you should not use your mobile phone in a crowded place: Somebody may be watching.
One woman did and is probably paying a heavy price for it now.
Sisters Delana and Brynn Hinson were watching a baseball game in Atlanta when they saw a woman sitting right in front of them texting.
The woman was with her husband, Mail Online reported.
The sisters realised that the woman was sexting a man saved as "Nancy" in her phone.
They took pictures and tweeted the photos of the seemingly adulterous text messages they claimed she sent to "Mark Allen", which have since gone viral, Uproxx reported.
Uproxx is a digital media company and blog network which focuses on linking web culture and traditional entertainment.
Miss Delana then passed a handwritten note to the man which read: "Your wife is cheating on you. Look at the messages under Nancy! Its really a man named Mark Allen. There is pictures on my phone (sic)."
She also told him that if his wife had deleted the messages, he could contact her at the number she included in the note.
She ended the message saying: "Sorry, just thought you should know!" The New York Daily News reported that one message from the wife read: "My love… Mark Allen I lov... much..."
"I will be the naked... laying on the ground (sic)," another read.
Miss Brynn then posted the pictures on Twitter with the following message: "When there's a married couple in front of you but... ain't loyal so me & @lanabaybee8 expose em! #Nancy #ormark."
Miss Brynn described the couple as having been married for 29 years and said "he had no clue" that his wife was cheating.
It is unclear how Miss Brynn knew the details of their marriage.
The sisters said they handed the man the note as he was leaving, before he stopped and turned around, giving them a thumbs up.
They claimed that 30 minutes later, he messaged Miss Delana asking for the pictures.
But not everybody was impressed by the sisters' detective work, New York Daily News reported.
"Yeah it sucks that she might have been cheating but it was really none of your business," @steelerfan1874 reacted.
"You should have paid attention to the game instead of the people in front of you."
"No one safe out here any more," @PizzaPartyBen added.
This article was first published on July 26, 2015.
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