I get pretty nervous when getting something I did not ask for. There are some lousy folks out there who get angered at the drop of a hat. Some time ago I was a waiter and never really took pride in my work, but I would always treat the customer's food above how I would like it myself. I've seen dropped rolls reappear on a plate and have heard of stories. Also, may be a bit off topic, but at McDonalds I wasn't sure what I wanted and changed my order. When I got my breakfast there was a nice wad of pubic hair under the biscuit. Should've tried to sue but whatever.
Anyway, you never know how sorry the people are that you can deal with. Its a delicate balancing act to handle people that I cant learn. Too stern and they can deliberately leave a bolt loose or drop something in the oil fill. Too passive and they'll just change the oil and leave the old filter...as examples. Not very many people are truly professionals. Remember the state trooper who pulled over an SuV and got a royal cursing. He remained calm and refrained from opening up a can.
Of course, if you have a trusted mechanic you can bypass all these feelings of uncertainty. You never know what goes on behind closed doors. I try my best to do everything I can to care for my vehicles myself, but when something is over your head all you can do is take it to the shop and hope for the best.
Anyways, if you're not living in an apartment complex, I suggest you change it yourself if you're worried about it being too thin. Or you can drain into a clean pan and reuse it in the winter or mix it with 10w40 in the future. Dealerships are for warranty claims and independents are for anything over your head. It is up to you for the rest.