as we all know, gooping is just an attempt to hide certain ideas from people since you can't patent a circuit. It's more of a deterrent for people, which translates to ......if you want the knowledge, you're gonna have to work for it lol.
I don't think gooping is bad if it doesn't hinder servicing, although there are better methods of hiding your circuit.
With that said, and in playing devils advocate here. there is a difference between buying a KLON pedal that already has this done to it stock then sending YOUR AMP , which you own ,and having someone shit all over it with crap making it tough to service. I do think that if an amp modder decides to use that type of method, the consumer should be made away of this before the amp is sent. I do know of some transactions that were done by modders where the amp was gooped up without the owner ever knowing that this would be done to the amp, and to me, that's not cool at all. (Not saying that all modders aren't up front with this!!) With all this crap said, if people are made aware before hand and they send the amp in then no harm no foul and I can see why an amp modder would want to hide his/her circuit. That's just my 0.02