You have dedicated facilities who let you sleep there and monitor you. But apnea can be easily seen, the person has gaps in breathing during some parts of sleep, gasping. Snoring can be one of the symptoms but reverse is not automatically true.

My boss was diagnosed with apnea in his 30s. It was so bad they didn't believe his first test results and had to redo it, off the charts. According to him it literally killed his father. Once he started using the device for sleeping he had 100x more mental and physical energy, everything was just easier.