From the dealings I've had with some in IT, I think part of the problem is they dont understand exactly what we do in the real airport world...
And, they won't unless (as you pointed out), they get out on the front lines. However, I would make one change to your suggestion of telling them that their numbers will tank, etc. When I was in the IT world, an application development team had to go out and
work alongside the workers until they had a good grasp on what the day to day job entailed. I don't care what the job or the industry, there is a "computer world" truth that can not be denied. There is the way management says the job is done, and then there is the way the job is done in the real world. Policies and procedures are all well and good, but no manual covers every situation every day.
In a country where people tend to define themselves by what they do for a living, most people try to do a good job. (Stands to reason when your personal self-esteem is tied up with your job.) When computer systems/policies& procedures/physical plant prevent the job from being done the way it "should" be done, the front line workers will find coping methods to get the job done anyway. (Those that don't usually just quit in frustration.)
The IT team probably can not do anything about the policy and physical plant issues, but there should be no reason that the maximum number of "unexpected events" (that happen everyday

) are not addressed in the computer systems that support the job.
Getting out on the line and doing the work is the way to get the IT team to understand what actually goes on at the airport. When I was in Application Development, I learned the job I was supporting well enough that I could pitch in and help when necessary. The IT people who support the ticket counter/check-in apps, should be able to issue a ticket or check-in a passenger, at least for the "easy" ones. And, should understand the steps needed to complete the "not so easy" ones.
But, as long as airlines are run by the accountants, such suggestions will be considered too costly.