

If you are 20 years old, expect to live to 100, and can imagine maybe spending $1 million per year, your maximum lifetime expenses are only $80,000,000. Once you have a large enough share of this that investment returns can earn the rest, you do not ever need to work again
The threshold for “no need to work” is way lower than $1,000,000,000. More than 12 times lower, in fact.

These warnings DO serve a purpose, even when they are legally void. People tend to follow less closely behind trucks, secure their belongings when parking, and take other actions to avoid the clearly indicated potential loss.
If a load breaks and cracks your windshield the truck is likely liable, but depending on how close you were following you may share some liability as well – especially if you, say, collide with the truck or another car after your windshield breaks. The law may hold that the sign has no effect, but itll be hard to convince a jury that you didnt know the truck was a potential hazard after you say that you saw it.