I popped to the local supermarket this morning to do a small shop with my DS2 (19 months). I was just about to park in a mum and baby space when some arsehole in a fiesta came around the opposite way and took it.
The bastard was on his own with no children or any sign of car seats. It may sound petty but it really winds me up when people do it - including friends of mine.
One friend often goes off shopping with a 21-year-old daughter and parks in them. Her reasoning is that her 21-year-old is and always will be her 'baby' so she has every right to use it.