I've worked in repair shops for years, those sort of repairs show up all the time.
The worst I saw over the years was an F600 dump truck that came in with no brakes.
The first thing I noticed was that the front wheels didn't match, they a had different number of lugs on the wheel. My first thought was that someone used a wrong drum or rotor in a pinch, but it went much deeper and was much worse.
Apparently the truck had been in a wreck, they went to a junk yard and found another front axle, spindle, brakes, and wheel. They then cut the straight axle in the middle, and **** welded on another axle. FROM A DIFFERENT MAKE/MODEL TRUCK. Then they had the issue of the tie rods not fitting, the threads were different sizes so they eyed up the front end alignment and welded the new/used tie rod end onto the tie rod that was already on the truck. They just overlapped the joint and ran a bead of weld down each side.
The front axle had four pieces of angle iron reinforcing the weld. The brakes on that wheel weren't connected, there was a vise grip on the hose ******* to the leaf spring.
The truck belonged to a local mason, he ran it up and down the highway daily. When I asked how long it had been that way the guy said he bought it that way years ago. He had been running it that way for years.
We refused to work on the truck and told the guy if he drove it off the property we would call the state police.
It wasn't the only really unsafe repair on the truck, it was in no way worth fixing.
He blew a gasket and called the police himself, we showed them the truck and they made him tow it away. A week later I saw it drive by in the same condition anyway.
My concern about welding a ball joint in like that wouldn't be the weld failing or the grease being overheated as much as I'd be concerned that the weld would leave he control arm with stress or possibly weaken it in that area causing a stress crack or gradual bend.
Are you really doing a customer a favor if the repair you do may only be putting an otherwise unsafe car back on the road? Usually cars that have those sort of repairs or owners that can't afford a proper repair have many other issues that have been neglected.
The number of vehicles on the road everyday with serious safety issues would astonish most people. I worked in a seashore environment for several years, it got to the point where you would drive the car up on the lift before even test driving most of them. I'd find fuel hose used as brake lines, copper tubing for brake lines, missing lug nuts, lug nuts on backwards, disconnected brakes, doors that don't latch, rusted through frames, rusty brake lines, broken seats, exhaust leaks on cars with rusted out floors, you name it. When you gave them a $3k list of work it needs just to go down the road most people got mad and threw a fit.
I started putting cars on the lift before test driving them after driving a car on a test drive and then putting in on the lift to find a tie rod with no nut on it and half a roll of duct tape holding it in place.