If your toddler manages to dial 911 (and they will—buttons are magic to them), don’t scold them on the call. Let them talk to the operator, who will likely ask to speak with you. Take the phone, apologize, and explain it was a toy or a fumble. Teaching kids about 911 is important, but after the call, have a calm chat about when it’s okay to use it (real emergencies only, not for pizza or missing toys).
One mom I know told her kid, “911 is for when the house is on fire or someone is very hurt—not for when you lose your teddy bear.” The kid now calls it “the fire people.” Progress.