I had a similar concern about my first TT. I was told to run the tires at 40 PSI because the trailer was 'light' and the recommended 50 PSI would make the trailer ride rough and possibly shake things loose.
After 2,000 miles they started to show noticable wear and an under-inflated wear pattern. After pushing them up to 50 PSI I was able to get another 3,000 miles out of them - but the damage had been done.
So after 5,000 mils - I had to buy new tires because they were worn out.
Running trailer tires under the recommended max pressure causes them to wear out faster.
There is one time to lower tire pressures below the recommended pressure - beach driving. In that instance the tires of the TV and the trailer need to go to the minimum which maintains tire shape. And air them back up to the recommended pressure before driving on hard road surfaces.