This has a meaning. It is the symbol of St. James Way to the cathedral of Santiago de Compostela, in Spain. People that do the pilgrimage like to get this tatooed to remember they have walked the way . And this is also why it is on a foot.
This may well be a tribute to walking the pilgrimage to Santiago de Compostela ( the Way of St Jame or the Camino). It would be more effective if it were not yellow and red (the colors used by Shell oil).