Where does the research sit for using weighted blankets on children under 3 for sleep?

Red Nose recommends using light weight blankets tucked in firmly to prevent head & face covering, for babies/toddlers sleep environment.
https://rednose.org.au/article/how-much-bedding-does-baby-need

Weight blankets are not recommended for infant/toddler sleep, as they have been associated with deaths in some children.
Please see article below:
https://rednose.org.au/article/weighted-blankets