GETTING THE BEST DEAL
It is a general rule that reading the fine prints in a contract or paper that you need to sign is always a must. Travel insurance, like most insurances has a lot of loopholes. Some policies only kick-in under certain circumstances meaning, not all the reason that you can think of is valid for a claim to your insurance company.
In most situations, it is better to purchase a travel insurance only AFTER booking for a trip and not beforehand.
Another important thing to remember is it is not a good idea to purchase an insurance from the same company that you bought a travel or tour service from.