Dollar is not the worst car rental agency I've worked with but its not the greatest either. Yes, the agents will automatically lead you to purchase their insurance but you have to stick to your guns and be firm and say no. My usual statement to them when they ask "are you going with our premium insurance policy or standard policy today"? My exact reply is "I am declining all insurance". They will give you the song and dance and that you are financially responsible if anything happens to the car and scare you by saying if the car is damage you will be charged each day its out of service. Well guess what? You in Vegas and you're here to gamble!
Think about it....If you're staying on the strip, its only 2.5 miles away from airport, you're not going to spend too much time on the road. Most likely, you're just using the car to hop from one hotel to another and logging less than 40 miles for a 3 day rental. Plus check with your own insurance company to know whats covered on your rental car. Also check with your credit card company to see if they provide any additional coverage.
The insurance add on is total BS. The rental companies make a lot of money off their customers by scaring them into purchasing it.