The Policy Document is an insurance contract between you and your insurer. Both parties (the policy holder and the insurer) are expected to honour the contract. What you have learned yourself, or what your financial advisor has told you about your policy, or even what you may have read on the internet about the plan may not have provided the full details, and is therefore not sacrosanct when you are making a claim for a variety of reasons; what matters and is vitally important, is what is written in your policy document. Therefore, the importance of reading the Policy Document very carefully cannot be overstated.
You must be honest when you are applying for insurance because the insurer can reject your claim if you did not provide the known, correct and accurate information when filling the application form. For example, if you or your family members have pre-existing medical conditions, you must disclose them to your insurer. If you have lifestyle habits like smoking or regular consumption of alcohol (beyond certain limits), you must disclose the correct information, otherwise your claims may be rejected. If you know that you are at risk of being made redundant in your workplace, you should not apply for unemployment insurance because you may not be eligible to make an unemployment claim.
Sometimes insurance buyers fear that the cost of their insurance policy may go up if they are totally honest, but the cost of dishonesty can be higher because the insurer can reject your claims, if they think that you have not provided them the correct information. It is always better to pay the appropriate premiums and be eligible for claims than paying lower premiums and not being eligible for claims.