Indeed. I have had a cell phone for years and I have NEVER (yes, never) had it ring in a court, a movie theatre, a restaurant or in church.
Every phone I have ever owned has had a screen that shows whether the phone is on or off. And once turned off, I've nNEVER had one turn itself back on without my permission.
Watch how the phone owner reacts when his/her phone rings in an inappropriate place. Do they answer the call? If they do, then they really intended to have it ring. A truly embarrassed person who did NOT want the phone to ring would simply push the talk button on, then off again without answering the phone.
Some phones have stupidly-placed power buttons that can get pressed when a phone is loose in a pocket with other items. Dumb design, but some phones are like that.