A claim can be denied if you fraudulently fill out an insurance application. Let's say you state 30 days max. You have a million dollar claim based on you seriously injuring someone.
The insurance investigators start interviewing your neighbors, family, friends, etc.asking about how often you go traveling. Where is your mail being delivered? Did you have the cable TV turned off at home? How much electricity have you used over the last few months vs a normal month? They subpoena your credit card records. They find you have been charging gas away from home for the last several months. They detect your fraud. Claim denied.
Best to not try to deceive your insurance carrier. They are very good at spotting fraud.