6to4 on Sprint Wireless Broadband

A few months ago, is appears that Sprint started dropping 6to4 encapsulated packets. Egress is fine. Ingress silently drops. Anyone see anything similar? Or am I the only guy crazy enough to be doing this sort of thing in the first place? -- . ___ ___ . . ___ . \ / |\ |\ \ . _\_ /__ |-\ |-\ \__