That's because a cage crinoline could spring up and expose everything underneath.
From the stltoday.com
Before the invention of crinoline, women's underwear was often very large and bulky.
From the en.wikipedia.org
The strapless tea-length gown looked dated, and the poufy crinoline silly.
From the bostonherald.com
Then you'll need your fur tippet, a crinoline, muffler and a chaperone.
From the independent.co.uk
Worn in combination with the corset, the crinoline was fashion at its most uncomfortable.
From the time.com
Ladies donned crinoline dresses and gentlemen wore their bowler hats to play a few holes.
From the halesowennews.co.uk
The petticoat, Day notes, was made using 17 layers of crinoline and a wire hoop for support.
From the courier-journal.com
The invention that revolutionized women's fashion in the mid-1800's is the caged crinoline.
From the theatlantic.com
Browne used tennis as inspiration but added drama with crinoline.
From the washingtonpost.com
More examples
Hoopskirt: a skirt stiffened with hoops
A full stiff petticoat made of crinoline fabric
A stiff coarse fabric used to stiffen hats or clothing
Crinoline was originally a stiff fabric with a weft of horse-hair and a warp of cotton or linen thread. ...
(Crinolines) The framework of hoops used to support cladding over a boiler. Named from the similar hoops under a crinoline skirt.
Petticoats stiffened with horse-hair to enable the bell-like skirts of the early nineteenth century, that was eventually replaced with the bustle.
A lightweight, plain weave, stiffened fabric with a low yarn count (few yarns to the inch in each direction).
A movable framework around the cone which can be moved up and down to restrict the cables tendency to whip if the distance from the top of the stow to the bell mouth is too great.
In the 1840s, a crinoline was a stiff petticoat made of horsehair and thread; by the mid-1850s it had grown to a light, cage-like framework of whalebone, wire or watch-spring steel. Unlike the hoop skirt, the crinoline spread to all classes, and was worn by factory girls and even peasants. ...