That's funny. Reminds me of some graffitti I once saw in a public toilet; "My boyf follows me everywhere" and underneath "I do not." XD
The nail polish graffitii basically started off a revolution; everyone after that graffitiied in nail polish. The teachers after threatening and cursing, just ignored it and eventually, it tailed off. Then they repainted the toilets again, and this time, it stayed away.