I don't see the probable cause for a warrant being issued here, unless there's something that's not being reported. the police have to have reasonable cause to believe that a crime has been committed to get a warrant from a judge. a utility man saying that a meth lab MAY exist is purely hearsay or speculation, and imo would not be grounds for a warrant. so either there is some info not being reported, or somebody needs to hire a lawyer and get paid.
as far as the handcuffing part, the police can handcuff you without arrest if they feel there is a possible danger while serving the warrant. it's called "detaining".
I have had several drug classes in my day, and the smell I've learned that most closely resembles a meth lab is cat urine. now, vinegar is not a pleasant smell, but I can definitely differentiate between vinegar and cat urine. so again, the guy saying he smelled vinegar as evidence of a meth lab is purely speculation imo.