I worked in banking for many years back in my early 20s...had an older client come in one day to cash out a GIC...part of our job was to determine why they were cashing out to see if there's any way of keeping the business...turned out he went to Florida for his annual trip, forgot to buy insurance and had a heart attack while down there...had to cash in his savings to pay the bill...very sad...
When I turned 65 I was no longer covered by my wife's group policy so I did an online application explaining the coverage I wanted and for a few hundred IIRC got insurance and paid by giving them my credit card info.
A few days later I got a confirmation in the mail, saw everything was right and filed it.
A few days later I hopped on the bike for a weekend moto camping trip to Virginia. Getting back late Sunday night.
Tuesday I got a letter in the mail from the insurer advising that I hadn't signed and returned the acknowledgement and wasn't covered until they got the acknowledgement.
Two days after that I had my first ambulance ride due to a pulmonary embolism. Treatment here was $50. In the USA it would have been X 1000.
A friend's F-I-L lied on his application to get a reduced rate and had a heart attack in Florida. When you sign you allow full access to your medical records.
The insurance company basically said "You lied when you said you were healthy. We lied when we said we'll pick up the tab."
On a typical application you will be asked what prescriptions you're on. You'll probably remember the heart pills but maybe not the lotion you use occasionally for dermatitis. Ladies, do you have a Rx for the pills? It's an Rx and in your name.
Some sketchy policies use any lie or error on an application as an excuse to refuse coverage. This isn't like car insurance where they check you out ahead of time and decide on the rate. They take what you say and only check things out if there's a claim.
You might be asked if you've had any medical procedures and say no. You think an ECG is a test not a procedure but the insurer says it's a procedure and you misinformed them, pay you own bills.
One thing about CAA is if there is an omission, error or lie they cover you but you owe them the difference between what you paid and what you should have paid plus a maximum of five grand.