Er... No? If you take someone's money in exchange for goods and services, you have a moral duty to give them what you said you would. Not a broken version of it– what they bought. If you explicitly state they're getting an unstable product, then sure. If you actually do your best within reason and your service is broken, shit happens. Nobody is perfect, but you made a good faith effort to deliver on your promise. But if you don't, and deliberately don't bother checking if it actually works while happily pocketing people's cash, that's unambiguously negligent. Ripping off small groups of customers is no morally different than ripping off all of your customers— it's the same immorality at a smaller scale so you're more likely to get away with it.