Oftentimes, they are sold as "bead grade" or bead quality wood. There are different requirements for beads and incense but bead grade is considered very high grade.
Usually, the wood isn't dropped in water to confirm whether it's sinking quality which is common otherwise. This is because the moisture and drying will cause cracking in the wood.
The oil content also should be high enough that polishing the beads after carving them will release oil that covers the bead completely. Some bracelets will have a rougher shape to the beads that don't lend themselves well to polishing. These are often considered more masculine looking so there's a benefit there but you'll usually find cultivated wood in these rougher, barrel-like shapes.
Then it's very difficult to avoid chipping beads while carving if the beads are too small. I've purchased a couple of bracelets from Russian Adam in the $150 to $250 range that was chipped (either during the initial carving or perhaps during transport). They were made of wild Papuan wood and had a wonderful smell. The imperfections could be easily hidden by positioning the beads to face inward (imperfect side) so each one appears perfect when worn.
The bracelets I have from grandawood ($2k+) were actually perfect though. They also gave me additional beads with my order so I could replace any damage that might arise later on ... or to easily sacrifice one bead if I wanted to do some testing.
Then if you find a bracelet where the beads are black with oil, the prices get really high and the likeliness of getting scammed also skyrockets. You can't look at these close-up and see the pattern of resin formation easily. They might have been doused with oud oil before polishing so recovering that sheen and odor later on by polishing it again won't be possible.
Finally, if it's a kinam pendant or bracelet ... don't expect any deals here. They are practically unaffordable so there should be a very high level of vendor trust as well as methods of confirmation in place. Burning is the best method but if you can see it being carved and make sure the "dust" is recovered, then burning that dust is the most economical option.
Getting scammed is sort of a hallmark of being a collector. Unfortunately, it's very rare for someone to be steadfast in this hobby and willing to explore new regions, vendors, and experiences without being bitten at some point. I'm glad you've been open about getting burned though. The best way to hold onto your hard-earned money is by learning from the mistakes of others so you've done the community a service by sharing that experience.
edit: grammar mistake corrected