Maybe, or it might just be who you deal with. Mainstream shops may balk.
Most places have something like a stock car track nearby ... buy a ticket, watch the race, and note who sponsors cars or advertises in the program, etc as far as mechanical work goes. Then call them monday morning and ask.
Chances are they do good work and they will be fine with it, but you can up your chances by talking to people at the track as well.
For what it's worth, I do both ... install my own stuff, and have it installed if it's something I feel is too important to risk. But, I bring the parts to the shop.
What mechanics hate is re-doing a bad customer install, or getting called up when it's been self-installed and it doesn't work. Know your abilities and have the right equipment on hand, but know when to say no to yourself. If you decide to pay for shop work, let them do the whole thing, start to finish.
For the parent question, substitute "HT installers" for "mechanics" and "shop work" for "an A/V installer" in that last paragraph.