@Kathleen1090
Just a thought I used to use the last 4 digits, might not be for you, but we realized we have multiple different renters renting independent units but close, if one guest gives his cell number for a text message or something to another guest. The other guest knows their lock code. Thank goodness never had a break in but I did witness an innocent number transfer for one guest to share a discount gas app with another,.
Most of us because we are asked for a pin everywhere have a standard one we use. I let my guests just tell me a pin and I assign it, Easier for the guest to remember.