I think the word "serviced" is a fancy word for "inspection".
Unless you're going to strip down the inflator mechanism I don't accept that my BC is being "serviced".
I think most divers are quite capable of looking after a BC.
At the end of every dive trip I leave my BCs to soak in a tub of fresh clean water for 24 hours with all the quick dumps open and operate the fill and dump valves several times.
I then fill, shake and flush the inside at least twice, normally 3 times, and then I pass my finger on the inside to make sure that I can't taste any salt. Dry everything thoroughly (inside & out), inspect all webbing & quick release clips, inspect & test all the rubber seals & inflator hose, check all the seams for stitches coming open, lube all the zippers, check the dump springs for corrosion, leave inflated for 24 hours to check for pin-hole leaks, and finally store with a little air inside.
On the first dive of each trip I pay special attention to the inflator mechanism, operating the button with both light and firm presses looking for any tendency to stick & then test all the dump valves, not forgetting the upper one on the inflator hose.
On my 4 familys BCs over the last 4 years, I've just had to resew a couple of seams that came unthreaded, change one rubber disc in a quick dump valve and clear one sticking inflator valve. This last was cleared immediately ( & permanently) by the simple application of a silicone spray - procedure recommended by the technician at the factory. The replacement rubber disc was cut from a bicycle inner tube - I found one with the same Shore hardness, very close to the value recommended by the factory, and has worked fine for the last 60+ dives.