Couple reasons to not bypass the solenoid .. 1) professionalism (If you can't restore an engine to working order to original specifications, it isn't a particularly professional thing to do) 2) product liability (someone has a backfire that starts a fire in their house, garage, or shed and if they can show it is because the solenoid was bypassed by the shop, the owner of the machine, as well as property owner, has solid case for a lawsuit)
Neither has anything much to do with EPA or emissions cops but plenty to do with product liability, if you are operating as a professional shop and business doing repairs for money, you can be held liable for bad stuff that happens because you bypassed manufacturer's designs (even if it's a crappy design to begin with) In today's Sue-at-the-drop-of-a-hat environment (and some people drop the hats themselves) you're gambling on your livelihood.
But what KE4 was probably referring to was local cops mistaking the backfire for a gunshot and getting trigger-happy. (A Tongue in cheek response, I presume)