What are the chances a future employer would contact your current employer without your express consent?

I’m applying to a new job in the same city and same industry, albeit different department, than my current job. My current employment situation is good, but not good enough that they wouldn’t be a little resentful and, knowing their personalities, perhaps a little spiteful that I would shun the opportunities they’ve given me in favor of something else. I’m worried that applying to this particular position would come back to “get me,” as I’ve seen a top-ranked employee’s name from the place I’d be applying to in our company’s rolodex. I know that HR departments, fueled by recognition of our litigious society, are particularly cautious in terms of obtaining prior consent before checking references. But what I’m more concerned about is “back-room conversation” between executives of my company and my prospective company, along the lines of “hey, I happened to glance at a resumé today of an employee who works, strangely, at your place—so, and between us of course, can you tell me what are they like?” I suppose all I can do is request that my application be reviewed “in confidence;” I suppose what I’m looking for here is a bit of moral support regarding the process and specifically whether anyone has experienced or learned of situations where this has backfired. Otherwise I fear that finding a job in a new city would be my only escape. I’m also concerned that a potentially spiteful higher-up at my current job would be so spiteful as to fire me at my current job and ruin my prospective employment at the other place… I doubt it, but I fear that happening if they are feeling particularly betrayed.