Barry,
That makes a lot of sense and boils it done to trading risk and assuming one risk is better than another, or the one risk is less than another…
If that is the only choice I too would chose the lower of the two risk… but without all the information it’s no longer a choice or even a assumption… it’s a guess…
If the choices is yours, and it is to install a tire that isn’t properly fitted with the rim, you have also added the risk of negligent liability on top of the higher risk of rim failure…
But fortunately that isn’t your only choice…
If cost is the driving factor, the first choice to reduce tire failure risk is good tire maintenance and not over loading or under inflating the tire (including while parked or stored) or exceeding the speed rating…
If you need tires anyway, just buying a better tire the correct size can reduce risk…
Up sizing to a higher capacity tire that correctly fits the rim and falls within its ratings (might require calling the mfg.) can be prudent…
or for a minimal cost the correct rim sized for the upsized tire can be added and would almost always be the best choice… almost because the benefit of upsizing reaches a point of rapid diminishing returns quickly…
or you could throw all caution to the wind and go all out cost be damned…
Balancing my newly and highly upgraded trailer tires…
I did need new rims… 13,200@131