It means everyone can order everything. Sometimes deploying code accidentally breaks some other part of the program, and when that happens it is usually the user who first sees the error. The goal is to reduce interruptions to the customer's experience in hugh stress times.
There are shipping cutoffs for a lot of sites, like order today and get it in 3 days, order before 1 and get it on monday, etc. The last cutoff that will make packages arrive before Christmas is definitely the most important one to not break. Fixes to super important bugs can still go out, but regulr changes, new features, etc are stopped.