The vast majority of people who deploy to a combat zone end up in no real danger during their tour -- do you agree or disagree?

Having operated on COPs for two deployments and FOBs for two others, I can say that the danger is "different." On a COP, the enemy danger is obvious and Soldiers have to deal with it on a daily basis. On a FOB, external danger is less likely, but the internal threat is significantly higher; however most personnel will get too remain oblivious to this danger, because friendly internal intelligence services are always at work ensuring servicemembers don't have to worry about getting killed in their sleep by a local or third country national they thought were their friends.

That is not at all to downplay the very clear danger and loss of life that the minority of forces face in remote combat locations. I'm just offering the difference between the perception of danger while deployed.

I've been to Chicago - there's dangerous tour. :/

There's an old adage. "The safest place you can be is surrounded by a company of fellow Marines."

The thing with deployments is you are skirting the line between levels of threat. Think about how we carry our rifles depending on whether we are expecting combat or not. The Alert (pointed to the dirt) for imminent (Severe or Critical threat levels) all the way to the traditional carry for low or moderate levels.

It's not that any single member is in danger.... but collectively our combined risk pushes up way up the charts. Kind of like buying a really crappy lottery ticket. Quantitatively, the chances of "something" going bad is just ever present. We're working with firearms, explosives, fuel, vehicles, heat (weather)... all things things just exacerbate our overall danger level.

You mentioned this discussion was between you and a Navy cohort. Ask him how safe a ship is. Just think about that for a moment. Ships are floating office buildings which we launch airplanes off of. But we train constantly on them for when things go wrong. And that's in "peace" time.

So to answer your question, I generally never felt in real danger (I come from a different era though), however there was LOTS of dangerous things happening around me.