The following is some long standing case law...
Wayne v. US, 318 f. 2d 205 (Court of Appeals DC Circuit, 1963)-Police, having a report of an unconscious person in a home, can force entry to check the welfare of the person as an exigent circumstance. Evidence found in plain view after entry is admissible.The Court stated, "Acting in response to reports of "dead bodies," the police may find the "bodies" to be common drunks, diabetics in shock, or distressed cardiac patients. But the business of policemen and firemen is to act, not to speculate or meditate on whether the report is correct. People could well die in emergencies if police tried to act with the calm deliberation associated with the judicial process. Even the apparently dead often are saved by swift police response."
Every case I've come across that deals with making entry based on community care taking has some wording about exigency created by the reasonable belief that someone could be in danger. It's not reasonable to make entry just because there is an unlocked, or even open, door. There has to be something else... A 911 hang up call, cry for help, someone visible (and unresponsive) laying inside, etc...
I don't see how a dispatched call about parking with an open door present would automatically fall into community care taking.
I think the best bet would have been to call from the door way, if no one answered then it probably would have been best to just shut the door. If you feel the need to make entry, just realize that anything you come across likely wouldn't hold up in court.
At least that's my 2 cents worth...
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