I can tell you that I have literally had a bull "stick his head" into the tent and bugle.
One of my favorite elk adventures of all time, a different adventure, I had already tagged out and took my kids up to elk camp for some Dad daughter time. I had been teaching them bugling. We had gone to bed. This bull walked through and let one rip right in camp. My daughter rolled over in her sleeping bag and said
"Dad, would you stop"

In another elk camp, we had two potential herd bulls have a screaming match one on each side of the camp. The both shredded trees in camp.
On another adventure I bugled a bull in for Idabooner. We sacked out under the stars. I woke up a couple hours later and there was a nice bull standing over Idabooner sniffing him. I was praying Idabooner wouldn't wake up and get stomped.
what they all have in common....time of year. In the rifle season I have had the opposite happen. I have pushed elk completely away.