General rule that less rep person sends first is good.
We clearly see that at least 5 or so scammers have appeared on this site in the past year. Everyone has to be aware and consider that possibility.
I don't want the burden of expectations not being met, so this is why I just share the beans I make freely. If the recipient of my beans has something they can share back to me, then I am grateful, but it is not required/expected. I probably sent beans to everyone who eventually was outed for scamming other users.
I almost never make an agreed trade, especially not with beans I paid/traded for. I have done that with only one or two trades, and the other trader had definite verified good rep with many confirmed shares/trades. For example, @BrotherRandall who has many many verified good reps and has a bean making co.
Overall, this has brought many nice shares to my bean library, and I am happy that other people get to try out the seeds I make. I would much rather receive beans people make in their own gardens too. For me, there is something more special about that than an expensive pack of hype.
On any situation such as this site as well as others you're bound to get bumped at some point by someone wanting something for nothing. Stick to the ones thats been here awhile and check their trade status , thats pretty much the insurance of a fair trade and the numbers speak for themselves .