I have an odd story for you all.
I first noticed this when i first went on holiday with my sister.  We had never shared a room before but did on this holiday.

One morning I woke up to find a bruise on my arm, one which looked like a straightish line, so i showed my sister exclaiming that I had no idea where it had come from as i hadn't banged it anywhere.  Her reaction was of shock and laughter, she explained to me that she had previously gone into the bathroom and slipped and banged her arm on the edge of the sink but had no bruise afterwards.  Then some time after the holiday (she lived with my mum and i lived with my dad, only yards away from each other) I woke up one morning to pain in my ankle, slightly swollen, it was rather painful to walk on and again i had no idea what had caused it as i ad not injured myself, so i asked my sister out of humour if she had hurt her ankle, her response was that she had.  The day before she had ran into her house and hit her ankle on the side of the doorframe but recieved no injury.... i did!
No idea what to make of it, is it coincidence?