Here's my experience with powerless.
A few WMAs I hunt have power lines running through them. There are no posted signs or any no hunting signs. I have never had an FWC officer say anything about not being allowed to access or hunt/shot on the that pice of land. I've haven't read anything in any of the specific WMA brochure.
I'm not say its legal or illegal, just my experience with power lines.
Take Care Stay Safe
GSM