Their fragility is greatly overstated. Removing the foliage will stop it from adding any more energy to its root system that year (and end it's reproductive efforts of the season if it hasn't yet formed seed), but a decently sized one can handle this and will still sprout the following season (likely not as large as if it weren't cut down). Repeated defoliation year after year after year can eventually do them in, but I think it takes some effort.
One of the bushes I regularly walk through has a scattered trillium population. Grazing cattle have access, they don't walk as gently as I do and they also eat Trilliums. There's no way any would be left after the many years they've had access if these plants were as fragile as some people make them out to be. I think intentions are good - if people believe Trilliums are so delicate they may be less likely to pick them, and I do support not picking Trilliums, but it's easy to get carried away when describing their frailty.
Note- I'm speaking of the more common Trillium grandiflorum and T. erectum species, these are the ones I have the most first hand experience with, others may not be as vigorous. Here's a study on T. grandiflorum where they chopped a bunch down to see the effect an early spring browsing by deer would have on the plants fitness-
http://www.botany.wisc.edu/waller/PDFs/Rooney.Waller.2001.HowExpDefoliation.pdf. Of the 31 they hacked off, only one failed to return the following year.