Warning: This video is graphic.
Flight Attendants are constantly asked “can I use the restroom” when the seat belt sign is on, when the aircraft is taxing and any other time they have to say “sorry, but no.” Rarely are they asked when they can respond with a quick “yes!” Flight Attendants cannot give “permission” to be moving about the cabin during critical phases of flight and ground operations because it is against Federal Aviation Regulations and the flight attendant would be faulted for allowing someone to violate the regulation.
However, crews also cannot restrain you in your seat after declining your request. So if you really need to go, you can make the best decision for yourself in your situation. It’s customary to allow those “emergencies” access to a lavatory. Well this Flightmare of a passenger decided to retaliate her “no”..while finishing her phone conversation.
Check out this video of a passenger who seemingly requested to use a restroom after boarding or just before deplaning on a Warsaw to London flight aboard WizzAir. She was told no and she decided to.. well.. watch it for yourself!