I caught this on Daily Planet on the Discovery Channel a while back. You raise an interesting point. Best not to cut those runners off and replant - just guide them where you want them and let them go!

I remembered from the link below that someone (in this case, hamiltongardener) mentioned a bed that was never renewed, fertilized, or mulched. I don't know if his father did anything with the runners, though he had everbearing strawberries instead of June-bearers. I think they have fewer runners.

Anyway, I may give the "leave-'em-alone" a try, at least not cutting the runners away from the parent unless it just gets too crowded after the first year. I'll start them in good soil and keep them fertilized and probably mulched with leaves in winter. It seems to me that if a strawberry plant sends out a danger-alarm to all its progeny if attacked, it really might be interesting to see if the defense really works for more production.

Of course, the same article notes that strawberry viruses can spread the same way, so I guess one might anticipate a down-side to keeping them connected, too.

The greenhouse whitefly is apparently a vector for a couple of strawberry viruses, and aphids spread other viruses, but the plants need to be open to the elements and insect pollinators to produce well: Allen and Gaede (1963) studied fruit-setting of 'Shasta' strawberries in the greenhouse and showed that plants caged and undisturbed by man, insects, or breezes set no fruit; those uncaged and undisturbed set 20 percent; those uncaged but receiving wind from a fan over them set 77 percent; whereas those that were caged, but brush pollinated daily, set 97 percent of the flowers. This finding indicated that the plants alone set few fruits, and wind has some effect, but insects may be more important than wind as pollinating agents. Couston (1966) also noted that malformation of berries was greater when adverse weather occurred at flowering time. He also obtained more number one berries from exposed plants than from plants caged to prevent insect visitation, indicating that insect pollination increased production.

http://gears.tucson.ars.ag.gov/book/chap7/strawberry.html

But if these disease-carrying insects are present, they'll spread the viruses whether the runners are attached to the mother-plant or not.

If I have a wipe-out, I'll not plant any more!