Earlier this year and today I’ve had two incidents with roll-on deodorant that was in my checked and hand luggage. Both resulted in a mess on the bathroom floor and /or the sink.
I think what happens is that the pressure in the hold or the cabin causes the roll-on ball to pop out of its enclosure, so when you remove the top, the ball goes flying onto the floor and the goopy deodorant sprays into the sink and/or the floor.
The first time it happened was in the showers in the Qantas lounge, so I wasn’t going to rescue the ball from that floor. The second time was in the hotel where I’m currently staying, but this time I rescued the ball before it hit the ground, however not before quite a lot of product went flying.
So if you’re traveling with roll-on deodorant, be careful when opening it after landing in case it goes everywhere.