Laws around insurance coverage when driving another vehicle?

If they aren't an excluded driver, it's covered.

Unless they live in your household and you with hold that information from the insurance company. For example if you have a 17 year old son with a valid drivers license and he wrecks your new car then you are fricked.

Legally, if you give permission to someone else who is not listed on your policy to drive & they are not an excluded driver then your insurance will cover it.

Beware of letting anyone else other than who is on your policy drive your vehicle as your policy will be the first in line of coverage for any accident that happens in your vehicle. Remember, you are paying premiums to cover the people who are listed on your policy & nobody else.

Once the insurance company finds out you are letting other people who are not on the policy drive & they are in accidents in your vehicle there will be an Underwriting Review & your Agent will be talking to you. Don't let them fool you. Any accident even if it is not your fault could cause your rates to go up. I highly recommend only letting people listed on your policy drive your vehicle.

Your coverage is primary, theirs is secondary. Unless they were using your car as a temporary substitute , then theirs would be primary.

It will not count as an at-fault accident for you, but underwriting will likely ask you for details and relationship.

Right. You can let someone drive your car and your insurance will cover it.

There are exceptions such as if you rent it to them or they drive it for extended periods regularly or for a commercial use more than incidental to the job.