I have never heard of that so not sure but if you freeze the cake first and then do a crumb layer it turns out great. Look up Wilton.com or I am sure you tube has a ton of videos on how to do a crumb layer
It is possible to put powdered sugar on top of a cake before putting the icing. However, this method of garnishing the cake is not common. Another way of frosting the cake without getting crumbs is to first put a thin layer of icing and then let it sit for an hour in order to seal the moisture. Then, you can finish off with the process using the ingredients that you have.