A couple of months back I made a Helles. Still trying to get my induction boil dialed in, after primary fermentation I had some leftover beer so I decided to do an experiment. In general, when handling my beers I always purge the receiving vessel with CO2. So I did that with the big carboy, then siphoned the remainder of the beer into a one-gallon glass jug. I lagered both for the same amount of time. I packaged the one gallon batch into sixteen ounce PET bottles, carbonated with one sugar cube (approx. 3g sugar) each. I packaged the main beer, again, packaging part of the beer as above. Then I let the bottles condition. Last night I had SWAMBO pour both beers into labeled cups ("A" and "B"). I did not know which beer was in which cup but soon could tell the difference. One was darker in color. The lighter beer was also "brighter" in flavor. In short, it was easy to pick out the beer that had been exposed to oxygen when racked to secondary. I've argued against LoDo brewing in the past and still will - there's a bit too much magic involved in doing all the steps exactly or the beer will be ruined. But this test tells me that reasonable precautions, avoiding splashing, purging vessels, etc. are worth the time.