Brushing them away may be impractical given how many cicadas can end up in the area (once the population has finished emerging, which they haven't to date), and given how often females may settle on the plant after flying-in from surrounding areas. That said, brushing them off is harmless, and it's unlikely the cicadas will choose to lay eggs in sequoia stems. Conifers in general are not conducive to their egg "nests."

You shouldn't have to cover the trees, but the risk/benefit assessment is up to you to decide - as you noted, netting may deform some of the new growth if it can't be adequately staked above the leader and branches. Egg-laying damage can be injurious or fatal to young trees, but only when the stems are a vulnerable size - about pencil diameter or so - and thus saplings with too-thin wood won't be a target. It depends on how valued the trees are versus the hassle of trying to net them while staking the netting (and keeping the contraption secure enough to not blow apart with each thunderstorm or heavy rain).

Unfortunately, Coast Redwoods are not well-adapted to our hot summers (including warm overnight temperatures) and heavy, compacted-clay soils, and so may struggle in future years regardless of cicada impacts this year.

Miri

Thank you for the advice. I’ll check them and from time to time just in case the female cicadas decide to accept the trees for egg laying. If so, then I’ll work a net around them with some staking. That being said, am I looking for a V shaped type incision as the nest and when would the females be ready to lay their eggs?

A slit running the length of the twig for a couple of inches is what you are looking for. There are images of this damage on each of these pages:

https://extension.umd.edu/resource/cicadas

https://cicadacrewumd.weebly.com/gallery.html

Miri