This past weekend, I replaced my tires on my 2008 Tahoe trailer and discovered that none of the wheels had been balanced. It was delivered from factory that way. Just want all of you to be advised to check your tires/wheels frequently.
To answer your question...YES...it does cause vibration and stress on the entire trailer. But most trailer manufacturers don't have their trailer tires/wheels balanced for obvious reasons, that being cost... But I will have my trailer wheels/tires balanced for that exact same reasoning...even the spare as well. Any time you can prolong bearings, seals, and even welded joints, I think it is a good thing... Balancing things does make them last longer and run both smoother and quitter but also cooler... Known fact!