The 'heavy' tag is not there to embarrass you.
Health & Safety guidelines set a limit of 25 Kgs as the maximum safe lift for a single man (16 Kgs for a woman). The 'heavy' tag is put on bags that exceed 25 kgs so that it is marked as needing 2 men to lift it - where the H&S limit is 32 Kgs.
Anything over 32 Kgs should strictly go as cargo, where fork lifts etc. are available.
The TSA will not search bags on the way into the US (they are trying to prevent incidents on planes) - US Customs might search on the way in, but you will be present.
On the home journey, TSA will screen 100% of baggage using X-ray equipment - if they see anything suspicious, they will open the bag and manually inspect. If they cannot immediately open the bag - either with a master key etc. or cutting off a cable tie - then they will force it. They will not compensate you for any damge.
The suggested method of fastening a bag is to use a very tight cable tie - this provides similar protection against casual theft or bag burst as most of the silly little padlocks - but is easily cut off by TSA. If they open the bag, they will insert a memo to that effect and reseal the bag with a blue TSA cable tie if possible.
We have had bags searched (perhaps it was ambitious packing the blender - lol)but no damage. Our travel insurer accepts that cable tie count as reasonable care.