Filtering policies

I apologize in advance if this subject has been regurgitated. I would imagine it has, but a quick search of NANOG archives reveals nothing. What is the "party line" among providers as regards to BGP route filtering? I have a customer with a /24 (grandfathered) who now seeks to multi-home. Is their /24 globally routable? There's no way they can justify anything less specific than a /22. Are there any other solutions? Regards, Tim -- Timothy | tim (at) tux (dot) org | 4FE3 6D8E 5F7A 61E9 27B9 | NSP/ISP/ASP Brown | Encrypted Mail Preferred | 9220 B6E5 F181 4A94 11C3 | Engineer