The problem he was doing an illegal and unauthorized modification of an electrical device by doing so he was also doing work with 120 volts AC which means he must have an electrical license or otherwise be qualified to do this type of work depending on state he lives in.
The problem is the garage door opener is a UL listed piece of equipment when it is submitted for approval this is how it is to be built and maintained any modification violates the UL label and puts the person doing the illegal modification in serious trouble and fully civil as well as criminally liable should there be a fire , injury or god forbid death as a result of the modification and since the work was not permitted to be done the technicians insurance carrier will not provide them coverage as well. I know of a handy Man who lost his home and job and ended up committing suicide over just such an incidence back in late 60's some one brought him an Electric Hedge Shear which the trigger switch was not working he bypassed the safety switch and drilled a hole in the case and attached an on/off snap switch problem solved or so he thought the neighbor took it home and couple weeks later when his son was using it to trim the hedges he fell and instead of his finger holding the safety switch and losing his grip and the safety switch shutting off the shear the shear stayed on and the boy lost 2 fingers . The handyman was sued and lost everything defending himself in court he lost his job because he spent so much time defending himself and after a court judgement of $300,000.00 against him meaning he would loose everything he put a gun to his temple.
Another man in rural county by us ended up facing Negligent Homicide charges after being a handy helper and fixing a fence charger and a young girl died after getting shocked by it and not being able to let go because he wired it wrong .
Any time you modify something electrical and do not do so properly you put your self in jeopardy. Its not worth it . This is why a professional will often turn down work when he knows its not something he is permitted to do. I have turned down many electrical jobs for this exact same reason myself.
I warned this individual he is not permitted to do this type of work and he is liable if there's a problem and just does not get it. He will when something goes wrong and an attorney researching the case sees this article and his postings on face book . But some times people do not learn till they end up being sued. Seen it happen all too many times with people who think they know what they are doing with electric and should not be touching it. till its too late and then its run duck and cover and there calling me crying because they have gotten them selves in trouble and what do I do now and i tell them you where warned and I hang up the phone. It is just a matter of time till Neal , Frank Andy or Jimmy will be calling me and I have repeatedly warned them they should not be doing electrical work but they will never learn till they get burned by it.