The problem I have with that is that some person who is really poor and destitute might really need the kids bikes and scooters. You don't.
I totally need to apologize for my previous emotional response (comes out every time someone tells me what I do and do not need). You are right, I don't need kids bikes or scooters, I'll look ridiculous on either of them. But you know what, you'd be hard-pressed to find somebody in the US who NEEDS used bikes and scooters. Scooters are completely out of question, they aren't faster than running and you cannot use them on any terrain (much easier to run on a grass, than ride a scooter). So the NEED for scooters doesn't exist.
Now bikes, well, kids who really NEED a bike are those who have to cover some substantial distance on feet, like 5-10 miles, possibly on a daily basis. I don't know if there are kids who do that in the US now (the key word is "now"). Could be in some very rural areas, but I doubt they don't have a bike already or will appreciate getting a used one from some city kids. I actually challenge you to gift a used kids bike to a family in NEED of a USED kids bike. And don't use CL or Facebook, there is no way to know for sure.
You might find 3 options:
1. People like me, who can afford buying, but don't buy. You think those people should just buy, and off course they won't, because they don't think they need it.
2. People who can't afford buying a bike, but do that anyways. Try to give them a used bike. They might even through it away or get really offended, because some "rich gal/dude" gave them a USED bike. Those definitely don't need it, and are going to buy brand new (that's my tenant).
3. Some refugee families (definitely need a bike). But if you try to donate a USED kids bike to a family, the SW is going to nicely tell you that they either accept a quality brand new or a quality used (translation: high end bikes, not some cheap-o hand me downs, you can't sell).
So, please, try and donate a used bike, and then report back. I would like to change my opinion that I'm (and other people in the category #1, aka mustachians) the best candidate for used kids bikes. Otherwise, I'll have to think that your response was baseless and was merely provoked by your jealousy of some single mother owning "several rental properties free and clear."