I've never heard anyone say anything like that for any park, why would anyone object to something that would be there to make them safer? There are people who carry around weapons, and while I'm not saying park violence is a common thing, I'd rather wait an extra minute or two to know no one has any sort of weapon. And just because they haven't had any issues doesn't mean they don't need them. Don't wait until something happens to install them, install them right away so nothing ever will happen.
Believe me, with the time I've spent in and around parks in my time, I've heard plenty of people comment saying "this is confidence inspiring" when the first thing they do is go through metal detectors and pat downs. And like I said, the extra staffing and cost of that infrastructure has got to be absurdly high. There are parks all over the place that have no bag checks/metal detectors at the front gate and remain perfectly safe.
Just because one or two morons act like idiots doesn't mean the park should have to spend tons of extra money and man power in response to it. Punish those who do it rather than inconveniencing your company and future guests. I could go into a whole rant about how our country is too damn scared of the boogeyman (thanks to the fear mongering media), but I'll spare that one for another day.
I agree with deathbydinn, It's better to have safety procedures in place before something goes wrong. You CAN "go into a whole rant about how our country is too damn scared of the boogeyman (thanks to the fear mongering media)" but that doesn't mean you know whether or not some homicidal psycho decides one day to come into Cedar Point with a gun and shoot up the place. If that were to happen, Cedar Point (and probably all of Cedar Fair) would sure as hell be installing metal detectors at every gate then. I doubt a security system would really be that out of reach for any major corporation to install.