That's not about hierarchy between contributors, but hierarchy between tags: 

Major tags vs. minor information:  Semicolons are bad in major tags (e.g. building or amenity), but are very well suited for minor and diverse additional information.

Existing tags vs. new tags:
The specification of "charge" already contains the syntax with a / to specify what the charge applies to, like children and adults or single and double rooms. New data should follow the documented schemes and not try to invent a duplicate way of tagging.