Hello, as someone that hunts public land often the "etiquette" should be that even tho you have as much right as anyone else to be there common courtesy should tell you not to go where someone else is. If you see a vehicle at a spot just move on to the next spot and come back to that one later when the vehicle is gone. If you had gotten up before sunrise and went in there would you like someone just piling in on top of you? Besides, if you get into a good morel spot do you really want to chance someone else seeing you picking them? 
On a side note, many public lands are state or federal parks and it is against the law to remove "ecofacts" from them without a permit. You may want to check before getting caught and fined. I buy my permit every year just in case, it costs me 25.00 for the area I hunt morels in.
Good Luck!
On a side note, many public lands are state or federal parks and it is against the law to remove "ecofacts" from them without a permit. You may want to check before getting caught and fined. I buy my permit every year just in case, it costs me 25.00 for the area I hunt morels in.
Good Luck!