Nah, just get your boat and "have at it" you will be fine. The fact you have even considered consequences of an unsuitable tow vehicle mean you are ahead 50% boat buyers
Yesterday I was following a baby Jag towing a Haines Hunter SF535, the poor Jaaag while it might have had the power certainly didn't have the springs in the back to keep its arse off the ground. I really was expecting to see sparks it was that low.
Nah, Govt department (NIWA and DOC).
Ya not wrong, when I was buying my new ute the dealer said "ok so we will put this tow bar on" and when I queried further he was gonna put a 1 ton towbar on a ute with a 3.5T towing capacity. If I hadn't questioned it I would have been stuck with a 1 T towbar and seeing as how my digger is 1.7T that would not be a winning combination. Cheeky bastards trying it on.
Oh and my 5.2m alloy boat is 400kg dry weight apparently so you could probably launch that with a car off a good concrete boat ramp if you were keen
My 4.5m fryan with motor, fuel, fishing gear and safety equipment is 700kg tow weight.