Those feeder roots (and their tips) are needed to uptake nutrients and moisture. I'd just be leery of unnecessarily tearing those teeny tiny roots, especially on a plant so young.
Perhaps the other surviving roots can make up for the defecit, I guess I'm saying I'd just be leery of opening it up to the light and air at all, but if it's working...

If you ever get to wondering if it's effective, a side-by-side could save you shitloads of time in the long run. Or did you already try that?

Also, I'm really not one to talk about caring for your roots, lol.
Keep in mind this was a mature plant. But I butchered the canopy and roots, lost my heater, (which killed all but this plant, and one other) but she came back strong.

http://boards.cannabis.com/grow-log/...ownsizing.html
Rusty Trichome Reviewed by Rusty Trichome on . My Root building routine...What do you think of it? Ok, Gang.. I like to force my seedlings to reach stretch for the water...so I will open up the rapid rooter and move the seedling down to its first set of leaves..I like to let them grow about a 1/2" or so and do it again...I will continue to do this till its just the right height...you will see what I mean as you keep doing this....I cut out the circle of plastic to let the rapid rooter sit right and the tap root can extend with no problems...it takes a couple of trys sometimes to get the Rating: 5