. They can. If the user is aware that the displays have a tendency to be wrong, and they either verify them or use their own trusted, verified thermometers/hygrometers and keep an eye on it for heat spikes. The biggest problem is many buy these unaware of the issues. They depend on the display, and aren't aware of their tendency to spike, especially with movement of the sensor. I've seen many get to hatch day and not have hatchers till 2 or 3 days later, (and lower rates) because the bator was running cooler than the display showed. And not every bator is off, but a good amount of them, enough so that it's really hurt their reputation.
