I have helped the occasional old lady across the road. I have also used local drug and alcohol services to score (this is fairly standard practice as anybody who has ever had a heroin habit will almost certainly confirm). I'm sure BL is used in such fashion too at times but - as with offline drug service providers - this is very clearly not the intent and is firmly discouraged and when witnessed dealt with.
On the actual question, I think it would be difficult to achieve. Whilst the
BL Mission Statement would fit well with many offline drug service providers there will also be others where there is some areas of conflict. Specifically when dealing with abstinence only organisations as BL clearly does not go down that line.
Many offline drug services are heavily (often more or less completely) focussed on addiction primarily with general harm reduction being a distant second place at best - you only need flick through the leaflets and literature presented at such places or speak to workers (and/or volunteers) to see that there is little knowledge of any aspect of drug use beyond alcohol, benzo and street opioid addiction.
Where offline drug services have wider scope (such organisations do exist I'm sure although I've not really come across them myself) I could see more scope for working together in some way or another but vaguely recall something like this being attempted once in the past and it all going a bit tits up which rather put the brakes on any subsequent toe-dabbling in these waters.