The biggest chance of strain on the front tie downs would be if you were rear ended by a speeding 100,000# coal truck. In that case, I wouldn't worry too much about what happens to the tie downs.

Ken
Well... The guy that owns the local tractor shop I use, got in an accident. He was on a curvy rod, towing with a crewcab F450. He had a 20' dual axle trailer. He had a ~50hp Ford tractor, and a disc loaded up. Tractor was chained and bound on all four corners. Disc had a couple chains and binders across it.
Some guy lost it in a curve just as the tractor guy was going through the curve. Barely grazed the truck, but hit the trailer HARD. Broke two wheel off one side; broke the stubs off the axles, tire, rim, brakes, backing plate and all. Tore the fender off. Bent a piece of 4" box steel on the disk. Hit a rear rim on the tractor.
The guy had to be flown out to a trauma center. Car was trashed.
My tractor guys trailer was totaled. Disc ruined. But, he was chained and bound tight. Neither the tractor, nor the disc, moved on the trailer.
I have been chaining and binding on all four corners, and over extra implements for a while. That accident just reinforced my earlier decision.
Extra chain and binder are cheap compared to a $12k tractor, $1500 trailer, $10-40k pickup, your life, and the life of those around you.
And, it does not take a 100,000lb coal truck to ruin your day
