The moment we think about numbers to identify, our memories would go to the prisoners called by numbers Khaidhi No: 123 etc. Getting numbers tattooed on one's body is considered as a sad reminder of some of the worst atrocities in the history of mankind. In the prison complex of Aushwitz (death) camp, the ruthless SS army would tattoo numbers for all prisoners starting from May 1940, then they started introducing series ( like currency note numbers), A,B etc. Some Jewish prisoners had a small triangle tattooed below their serial numbers for quick identification. The Number gangs of South Africa, at the basic level have one $ sign tattooed to identify with the gang. Numbers tattooed on the arm would carry a negative connotation and for me at least it would be undignified. Maybe like Mr.KVRR, we should have a small chip shot into our arms,like we see in Bond movies. I'm attaching a image of a holocaust prisoner with a tattoo.