Let’s think about what is more stable- a 4 leg bar stool or 3 leg? You can ask the same of a 4 leg or 3 leg bridle sling.
How about the use of 4 machine skates versus a load equalizing dollies? Stools, slings or load equalizing dollies, the reality is that when a load is applied, the weight is usually distributed unevenly.
The majority of times, the 3 leg will dominate stability. There are a couple exceptions to this, but if this theory is dismissed or forgotten, mishaps can happen.
For example, if a load is being off-loaded be means of a crane, likely the off-set center of gravity has not been precisely calculated or located.
The challenge comes when the load meets the dollies, skates or other transporter means. Because of the different point weights it is very easy to quickly overload the moving equipment. A good practice to consider would be to set the unit on cribbing or blocks first, then utilize jacks to lift and lower on your transporters.
This may take a few more steps, but if the long run, it increases your safety culture and will save costly damage to both load and transport equipment.