What is the experts' view of the desirability of washing fresh berries before they are eaten?

The best thing to do with berries is to eat them in season, when you can buy/pick local produce. Then, you should not have to go through elaborate rinsing procedures. (Soft berries like raspberries don't really like to be rinsed.) The main hazard in buying and eating out of season berries that come from very far away is that you don't really know what pesticides/herbicides have been used on or near them and you don't know if they've been handled cleanly, e.g. clean water and clean hands. ( I doubt if you would find insects in such produce---the pesticides do work.) It is not very difficult to raise organic berries (apples and other tree fruit are much harder); I do it myself with little trouble and don't worry about rinsing. The rest of the year, we eat what's been frozen or we wait for summer.

Strawberries represent a real problem as the pesticides used are typically systemic. They go into the soil and thus into the fruit itself. Organic farmers that I've talked to plant other flowers between the rows that attract benificial insects. That said, rinsing off dirt is not a bad idea, as you dont know what's gone into that dirt. We live in an era when food borne illness can come from just eating spinach or so-called "triple washed" lettuce.

I don' wash berries like raspberry, but do rinse harder berries like strawberries. For raspberry I lay outing clean paper towel and blast with a bit of air from a compressed air canister (buy at a camera shop) ... that gets the little critters out.