Who is responsible for the load if it is sealed,
the driver is responsible for load security, if it’s sealed and you are not happy then ask for it to be opened so you can check and get it resealed. unless its something like a container then you are only responsible for the security of the container to the skelly, not what is inside it 
Driver.
Why would a driver take a sealed load out onto the highway without checking the suitability of the load.
Seals are company procedures only.
Even a customs bonded seal can be broken, load checked then resealed before you leave the docks.
I once helped out a driver who had a mini JCB telehandler forklift hanging out the back doors of a container.
If that machine had fallen out, and a family car had driven straight into it at speed.
Who you reckon the judge would have laid the blame at.