Sippy for lunch time? XP: 9-12mo.

dizzykates

We have been EBF and DD gets BM in 3 bottles at daycare during the day. Lately she has starting leaving 1oz in her last bottle (they are all 4oz) so I am considering switching to a 3oz bottle midday and having them serve it in a sippy with her lunch. They have assured me they will finish it in a bottle if she doesn't drink the whole sippy. I'm curious how you went about introducing the sippy, if you used BM in it and how it went.  I currently have a freezer full of BM so I don't plan to wean or switch to formula or cow's milk any time soon.  DD is 9 months.