On the train today: a woman with the word ‘WAR’ written in block capitals on her hand. Why?

I write reminders on my hand. For example, the rotation speed when I’m taking off in an unfamiliar plane or when I have to buy a pint of milk for my tea (equally important). But ‘war’? Oh well.
When we were in Goa, Aileen had mehndi henna tattoos on her hand, like the picture, which looked lovely.

I’m sure somebody has already auctioned their hands as an advertising medium on eBay, but if not, I’m volunteering.