IMO, trailers and their suspension items are built at "minimum" levels (which means more profits for head office). Just at the edge of passing tests with minimum build spend. After warranty is over or year 5 (which ever comes first), I upgrade ALL my trailer's suspension parts. For example, install next size up axles, next size up leaf springs and next size up tires. For example, instead of 205 "C" rubber, I upgrade to same rim size with 215 "D" rubber. Or from factory 215 to 225s. Next size up means less stress across double/triple railway tracks and better ride as well. Of all the years of my many different types of trailers (re: RV, boat, utility, etc.), I've yet to have a tire blowout. And, yet to have leaf spring snaps either.
And if trailer axle doesn't have brakes, I replace axle (next size up) with brakes as well. For example, my one small utility trailer rated for 3,200 lbs max GVW now has 3,600 lbs axle under it and that axle has full electric brakes as well (even though my local law states any trailer < 3,000 lbs doesn't need brakes).
If worried about rubber blow outs, recommend upgrading to "next size up" as well. Especially if there's available space within the wheel wall cavity. And if you suspect your trailer as "minimum" leaf spring strength, upgrade its to its "next size up" as well.