The baseball bat method works, but sometimes can get ugly. A proffesional tool does a nice clean job, and the good ones usually don't crack the paint. If one of you socal guys bought one, over time, you could get the toold for free charging anyone you meet a small fee to roll their fenders....had a friend who bought one and within 3 years made a $200 profit.
Last time mine rubbed was when I had the TSW Revos on my car with 205/40s on them. I later put 215/45 on them and never rubbed. I'd really love to pick those up again and lower it so rolling my fenders is something I should do to avoid rubbage again!