Acceptable to ask seller for option to return a component?

there is an important difference between a return because not working properly/not as described, and you just didn't like it...difficult for both buyers and sellers...

Sure why not?

Worse they can do is say no. 

even if you return something on Crutchfield on Amazon, it's not without a lot of costs and consequences, so I am usually very careful with the return option.

Most seasoned buyers on audio forums have a different approach: research the hell out of what I am buying before buying AND/OR if I don't like it, will I be able to resell it at a loss I am willing to accept. 

I learned this early at my own expense and paid dearly. I bought new/open box speakers for $1500 that checked off all the wrong boxes: sounded terrible, had no value on the used market, a sneeze would scratch the veneer, etc. 

certainly agree there is no harm in asking...

There is harm in asking in that I believe many sellers would not sell to you.  If I describe the component as it truly is and safely ship it to a buyer, then the transaction has concluded.  No do overs.  It protects me because I have no idea (or control) as to what happened to the component after it arrived at the buyer's residence.  I guess I could charge you for the return option, but realistically why should I even bother.  Some people might not have the problem I with you asking, but I think most will.