don't listen to all this union crap they have no idea what they're talking about
if you have no intention of driving then you should absolutely take the position
any management position is only going to help your resume, and real world experience in supervising people is solid gold to employers
further, as long as you're not in some hell-hole FT preload operation, it's not a terrible job, depending on your boss
the last thing is if you do end up staying with UPS, there are a boatload of interesting jobs within the company for someone who is open minded and aggressive about opportunity, and they are night and day to a preload position
let me know if you have more questions