I have had a project on the back burner for about a year now to offer a BGP feed via a websocket to facilitate people playing around and doing research without allowing them to accidently spew crap into the DFZ. Shoot me an email if you are interested and I'll try to get it spun up this week.
Generally, your upstream won't allow you to spew crap. Route filters are in place. I run a small AS for hobbyist purposes and all my upstreams are locked down.