A cruise passenger’s viral post has ignited an unexpected debate online after they criticized fellow holidaymakers for storing their cabin keys in their bras.

The incident took place on Royal Caribbean’s Independence of the Seas, where one traveller expressed their frustration on Reddit over what they deemed an unsanitary habit. The post, titled “Ladies — Get a lanyard,” described observing women retrieving their SeaPass cards from bikinis and bras when entering cabins or purchasing drinks.

The user wrote: “I’m currently on Independence of the Seas and on two occasions, I’ve seen women reaching into their blouses to find their SeaPass, which they had stored in their bras.”

The comment continued with a stern critique: “This is frankly unhygienic for the crew members and for everyone who has them touch their drink glasses afterward. Please just buy a lanyard.”

Middle age woman standing on the sandy beach by the ocean (Fiordaliso/Getty Images))

However, as expected, not everyone shared the same level of concern. Responses soon poured in defending the practice as relatively harmless and even practical when lacking pockets.

One person responded: “It may not be the most elegant, but you need to relax. It’s just skin, the same as the skin on your hands.”

Another added their own experience: “Sweat. I have kept my phone there. It gets sweaty even if I’m not sweating otherwise.”

Others quickly put the situation into perspective, highlighting that passengers neglecting to wash their hands posed a much larger hygiene issue on ships. As one commenter noted: “People do not wash their hands with soap and water after using the restrooms.

“The lack of handwashing is so prevalent that cruise ships almost have to plead with passengers to do so before visiting the buffet. Boob sweat is the least of your concerns, my friend.”

Some users opted to address the issue with more practical solutions, targeting the lack of functional women’s clothing.

Women in bikinis sat by the pool on a cruise ship (Richard Baker/In Pictures Ltd./Corbis via Getty Images)

One suggestion read: “Dear clothing designers, why don’t you include pockets in women’s clothing so they don’t have to use their bras? There. Fixed it for you.”

Another simply declared: “Bras need pockets. I stand by what I said.”

Tech-savvy travellers also noted that the issue could be easily resolved if cruise lines provided alternatives to the traditional card system.

One cruiser explained: “From a customer-centric perspective, it would be better for cruise lines to offer NFC wristbands (in addition to cards). Give customers a choice. Personally, I find a lanyard incredibly bothersome.”

Others said they would prefer to store their passes digitally, like one user who said: “Let me put it in my Apple Wallet.”

Whether it involves tucking room keys into swimwear or reserving poolside loungers with towels, cruise holidays continue to spark heated debates about etiquette. For now, it seems the real waves are not in the ocean but in the discussions passengers have about boob sweat.