Apparently, such tattoos located on the lower arm would fool the Apple Watch’s sensors, which would then be unable to work as expected. An owner did mention that his Apple Watch that is worn on a wrist tattooed with black ink did not deliver a single notification, and the device will then lock each time his surroundings were dark. When testing out the same Apple Watch against his unmarked hand, it worked just as intended, which can only lead to one conclusion – tattoos and the Apple Watch do not mix.
Of course, one way of getting around this particular issue would be to turn off wrist detection completely, but this would defeat the purpose of getting the Apple Watch in the first place, since you will then be unable to take advantage of features such as Apple Pay. How do you think Apple will “fix” this inconvenience, if they see it as that?