I am liscensed Public Adjuster in Pa. In this state, as well as many others, a homeowner policy cannot be cancelled or rates raised for filing a claim.
There are 4 reasons they can do this according to the ins. dept.
1) Non payment of premium - I'd cancel you too!
2) Increase in liability - Install a swimming pool and deck w/ no gates or railings, usually give you about 60 days to make it right
3) Misrepresentation on application - you say that you don't have a dog but you actually have 5 pitbulls!
4) Fraud - you burn your house down on purpose and try to get paid for it!
Also, most policies give them the option that within the 1st 60 days, they can cancel you for any reason they feel appropriate!
They also cannot single one person out for a rate raise. Sometimes they have an across the board raise and they can do that also.
Now, I am not saying that people don't get canceled or have their rates raised sometimes, What I am saying is that it is illegal for that to happen unless it's for one of those reasons.
I am only talking about home owners insurance. Auto policies they can do whatever they want!
But if you ever feel like you have been treated unfairly by your ins. co., I recommend 1) call me, I don't mind giving you suggestions and/or 2) file a complaint w/ your state ins. dept. Insurance companies are scared to death of them and if they are doing something not quite right, the ins. dept. will set em strait!
In Pa here is a link to the Ins. Dept.http://www.ins.state.pa.us/ins/site/default.asp
This link is broken, either the page no longer exists or there is some other issue like a typo.