it means they either are in trouble, or they are there for a good reason.
I'd just say their in trouble.
"All visitors to the factory" is the complete subject.
Complete Predicate: must report at the office Complete Subject: All visitors to our school
all visitors to our school
All visitors to your school
The complete subject of the sentence "All visitors to our school must report at the office" is "All visitors to our school." This includes the main noun "visitors" and the modifying phrase "to our school," which provides additional information about which visitors are being referred to.
The complete subject of the sentence is "All visitors to your school." It includes the determiner "all," the noun "visitors," and the prepositional phrase "to your school."
all visitors
must report at the office
must report at the office
must report at the office
must report at the office
must report at the office