The construction dubs were a notoriously shady bunch.
Paid wages in cash without deducting taxes. Cheated on taxes, company and personal. Underpaid employees by not paying them for all hours worked. Committed fraud against insurance companies. Solicited work from fellow JWs but did inferior work at elevated prices. Underpriced and stole jobs from other brothers already contracted for that job. Dealt with black market materials. Stole materials from jobsites.
Those are just the ones that popped into my head without thinking that I knew of personally. I learned to not seek employment with most JWs who owned their own businesses. I also learned that if a JW with his own business was actively seeking to getting the friends to hire them for some project or job, they did inferior work, charged too much and were generally not to be trusted.
But to be fair, there were some dubs (a minority) who owned their own businesses who were honest. I learned to spot them also. They didn't talk about their jobs much. They didn't brag about being self-employed. They didn't look to get work from fellow dubs. A lot of dubs would not even know what business these brothers were in. When hired by a dub, they always had estimates, contracts and other paperwork to ensure no misunderstandings.
So, there were good but the bad outweighed the good at least 2 to 1. You wouldn't think that could be possible in God's true organization, huh?