Until you have supporting evidence, it remains a logical fallacy. As IBT and the IAM covers the economics for the hourly workforce, yes, I believe management will bear the hit. The 'hits' to IBT and IAM will likely be job loss through increased productivity, but churn "protects" incumbent employees from economic hits.
UPS (as other companies has done) could arrange for routine health screenings to look for signs tobacco usage. Employers have paid billions in health care premiums & claims related to issues deriving from tobacco usage. True casual smokers (those that you described) aren't the contributors to this problem. And yes, I know people who claim to have quit smoking yet puff on one cigarette a day believing (for whatever reason) it does not count. But these people are easily identified in health screenings.
Smokers are an easy target because they're easily identifiable. Although many alcoholics develop health problems, most don't display easily identifiable signs. Hence why some insurers ask to disclose DUI, rehab, or other alcohol-related incidents, in identifying alcoholics to penalize.