(the following text is extracted and summarized from AGUITBA manifest, guide association of Buenos Aires)

Among other things, the tour guide offers:

A professional, caring and committed.
Objective, free of bias and propaganda.
Reliable information and real, distinct from their opinions, stories or anecdotal data originating from traditions and popular legends.
Also, take care that every visitor respects the area you visit (monuments, attractions and local customs).
Oversees the planned itinerary, making sure to provide all program services.
Be attentive to the comfort and passenger safety.
Provides all necessary assistance in case of difficulty and / or emergency.

The guide guarantees a service, attention and professionalism. Displays an image we try daily value, respect and enforce it, make it known and taken into consideration in all tourist events, public or private. Those who act in this profession without charging fees getting their fair share profits at the expense of passenger commissions or favors should not be considered Tourist Guides.

Being the guide visible image of an agency, the first contact and probably the last, the importance of their presence and good image is critical as it will remain dormant in the memory of visitors.
Your guide must have a license granted by the competent authority.