Yep, I too am of the mindset to call and find out, with no shame or apologies, just be friendly.
It will give you piece of mind which is priceless. I might be forgetful to remember to bring an item along to return but I never forget that it isn't mine. I realize everyone is not me, duh, but I treat others the way I want to be treated and if there is some confusion/misunderstanding I have to clear it up so it doesn't create further problems.
If I find out later that I'm dealing with someone who intentionally borrows with no intent to return/rectify or they turn the story to benefit themselves, then I have just as much "right" to present my point of view and letting them know I'm onto them. I may not get the results I was looking for but I can rest knowing that I made it clear that I know what sort of person they are.
Not every confrontation has to be confrontational.