Would this be rude or is it justified?

So, when my roomates, my husband and I all moved in we all pitched in and shared groceries.. that stopped working due to them never having money causing my husband and i to buy food and them not paying. So we stopped that and all started to buy our own food.. but.. we decided we would all share milk and er and what not.. But.. one month later, its only been my husband and I buying the milk (8 big jugs to be exact) and 3 things of er... And they are using them.. but never buying them. I told my one roommate she had to buy the next milk and she said ok.. but.. we've been out of milk for 4 days now and she hasnt bought it yet, and she just stays at her boyfriends house, comes home for about 30 minutes a day to eat (using our milk) then is gone.. so she nver goes and buys it.... Would it be rude to start writing "Katrina's and Alex's Milk" on the milk jug and same with the er?