It definitely happens, I had an 085 number at one stage and a number of years after I stopped using it a friend emailed me and said she had phoned the old number by accident and the person who answered gave her a ream of abuse to the tune of 'who is this xxxx person that I keep getting calls for, she doesnt own this phone anymore, i do, im gonna get you...etc...etc...' - there were a lot of swear words in there too. I subsequently found out that a few people had phoned the number over time and the person was obviously annoyed that their number once belonged to someone else.