You are correct on not counting against baggage allowance, I was referring to weight load limit on the overhead bins. Depends on the plane as to the limit. I've not seen a problem in my travels, but I don't travel that much. My late wife was on self dialysis and her Solution and equipment could get quite heavy. I don't know the weight of your saline, but merely mention this for your consideration as you stated "it will only be an issue when trying to get it into the overhead compartment".