JMHO about trimming or tying up crests on crested breeds - I have two Silkies and when they are pullets they are very fluffy crested/bearded but after maturity and foraging around in the yard a lot of their crest flattens or mattes down and my Silkies nibble around each other's eye area only to clear vision and seem to do fine maneuvering around the yard and seeing predators or finding bugs/seeds. We find that whether our Silkies have fluffy full crests or matted down crests where they can see, it didn't change their behavior any. After molt when the hens grow in a new crest they tilt their head to see behind or above them just fine.
Chickens naturally move gingerly if a human is around whether the bird is crested or not. Every owner has to make their own decision but we never found it necessary to trim crests, beards, muffs, or wings but then we have a small cottage backyard and only 4 gentle hens - we have re-homed all our aggressive/assertive heavier dual purpose layer breeds. Polish and Silkies are aware their delicate heads are more vulnerable (vaulted skull has a hole at the top where the brain tissue is just under the skin). Vaulted/crested are more vulnerable to head pecks and injuries and will be more skittish than non-crested breeds. Trimming their crests won't preclude protecting themselves from possible head injuries. All chickens in general are nasty head peckers in flock politics and crested birds seem gentle or skittish because of protecting themselves from the other pecking chicken breeds. Cutting crest feathers will not do much to change this behavior which is why I don't put crested birds in a flock with normal heavy dual purpose LF layer breeds like RIR, BR, Orp, Wyan, Marans, Legs, etc. Most chicken breeds can survive head pecks from flockmates but vaulted skull, crested breeds, are more exposed to brain injury that can lead to seizures, wry neck, even death.
Hatcheries and breeders don't share this critical info so you see people tossing in their crested/vaulted skull birds into a backyard LF flock mix without knowing the risk of such a mix. If the owners are lucky their Polish or Silkies manage to avoid pecks from the LF but there are too many sad stories on these threads where chicks or juivies start showing symptoms of seizures, head-shaking, wry neck, or death, from a bewildered owner wondering why. Owners will insist their flock mixes get along fine and I can't dispute they dodged a flying bullet - my post is for information only and open for every flock owner to decide how to mix their flock since they know their own individual bird temperaments the best. For our own mix we had to decide on whether to have a heavier layer dual purpose flock or have a gentle crested under 5-lb flock. We get less and smaller eggs but don't worry any more that one of the gentles are going to be injured by a bigger assertive breed.