I'm a big fan of Murphy, and Murphy's Law dictates that they only time you do not take travel insurance, will be the time you will need it. It is a necessary evil and as we say in the business, if you can't afford travel insurance then you can't afford to travel. These days premiums are not too bad due to such a competitive market, you just have to take the time and discipline to shop around and read the fine print.
On tour, I quite often to mention that if you don't wear your seatbelt and there is an accident their travel insurance can be voided. However, whilst recently reading an Australian Travel article it stated, that by not getting the right vaccinations, your insurance could also be voided.
Travel Insurance Direct was quoted as stating “We will not pay a claim that arises… from a lack of due care and responsibility on your part by neglecting to observe appropriate preventative measures for the travel region as outlined by the World Health Organisation, including relevant vaccinations, malaria prophylaxis and hygiene measures".
So my point my fellow travellers, do your reserach and speak to your doctor. Don't leave it until the last minute as some vaccinations have to be done months before. Please don't leave home without it (even domestic travel) and read the fine print! I'd hate for you to learn the hard way.