how to not attract carrot fly when thinning

I think I read somewhere, that if you do not want to attract carrot fly when thinning out,then you should snip the seedlings , rather than pulling them. Is this true, as I have not yet purchased a fleece to cover them. Do people get a successful crop without  fleece?

I sow thinly in 6 inch wide rows, then don't have to thin the seedlings.  I also grow them between rows of onions, the smell of which may confuse/deter carrot fly.  No fleece is used.  There is usually a small amount of carrot fly damage, but nothing significant.  No-one nearby seems to grow veg, so that may be the largest factor as folk who grow in allotments seem to suffer the most.  If I were in that position, I would use fleece.

It's said that thinning - or, for that matter, harvesting - very late in the day or even after dark can avoid attracting carrot fly.