The I policy had last year was with all the high.limits as you were talking about andv5 mil umbrella, 2 mil and 4 mil Aggregate (I believe) wc limits were through the high. They did allow me to be exempt. But it still cost me 1300 a month. Not counting the bucket truck.Instead of 2k a year. Dont think its a issue at this point for me anymore, but I also would not pay that again to work. Ins agent told me 6 months ago they probably could not right the exempt wc policies anymore and she thought I was the only company that had one that they insured. There us a form in sc you can fill out but I heard most contractors will not accept as it doesn't follow their standard format. The form technically is not required. It just makes sure everyone knows. Their position so the sub cannot try to sue the primes wc. Or at least this how it was explained to me.
I was told years ago if you are sued for 1,000,000 and you have minimum limits ins may just pay the 50,000 you are insured too on regular insurance. Leaving you holding the bag. On the 950,000 balance. So I have always kept higher limits on my vehicles as it's my biggest liability. It may just be smart salesmenship on the agents part and it may just be scam. Not sure. Take care and Good luck.