my friend had a tat on her foot - she had wanted it in a different place to where it eventually ended up on the foot (around the shoulder reflex) but was told that the skin on the feet regenerates too much to have it put nearer the sole and that the dye would bleed.
i don't know if the pressure would have any long lasting damage to be honest - i mean it's more than likely that it would affect any reflex points it was done over, but i imagine once it has healed that it would be ok. put it this way, it wouldn't put me off having a tattoo...
Alx x