Enforcement of Authenticity
The strictness with which authenticity is enforced varies widely with different events and groups. While some consider only documented historical use to be authentic, and ban all inauthentic gear and behaviour from reenactment activities, others permit materials that plausibly could have existed, others permit inauthentic materials that can't be seen by the public, and still others only require that "it has to look authentic from 10 meters away" (i.e. from a distant audience's perspective).
Similarly, many groups permit equipment combined from a wider range of centuries than what could be considered historically accurate (e.g. 12th century soldiers wearing barbute helmets). This sometimes results from safety rules that require protective gauntlets and helmets, even when this interferes with historical accuracy.
In addition to mixing multiple centuries of a general period in a single event (usually to ensure a larger number of participants), some events feature more than a single period, especially if the event strongly focuses on combat displays or battles. In such cases, it is not unusual that the same reenactor participates in more than one show, sometimes with only slightly altered gear (depending on how strictly authenticity is enforced). A typical example is a clankie (a reenactor in full plate armour) removing his armour, picking up a round shield and participating in a Dark Age battle.
Many groups, especially in medieval reenactment, heavily promote the use of "market speech", i.e., talking in a way that sounds appropriate for the period. Inauthentic equipment and behaviour is often referred to via descriptive phrases like "pocket dragon" (for a lighter or box of matches) and "horseless carriage" (for a car or other engine-powered vehicle) to circumvent strict enforcement of authentic speech. Other groups expect reenactors to stay fully in-character throughout an event, and refrain from commenting on non-period items. To adequately explain activities to an audience, many such groups designate one or two people as "interpreters" who can step out of character to discuss things from a modern perspective.
Other ways to circumvent the need for authentic equipment include "hiding" plastic bottles (usually by wrapping them in cloths or furs), using "bindings" (long straps of cloth or fur) to make inauthentic footgear look more adequate, or simply hiding coolboxes inside wooden chests.
For safety and comfort, authenticity is usually restricted to designated public areas, thus allowing for the use of portable toilets and inauthentic tenting by reenactors outside these areas.
A typical issue among strictly authentic reenactors is the inclusion of female combatants, as this is a clash between authenticity (there were no female combatants in most reenacted periods) and modern concepts of sexual equality.
Similarly some groups enforce authentic hairstyles (e.g., 20th century soldiers are usually not expected to wear long hair or beards) and often (inauthentic) jewelry is not permitted—although in combat reenactment this is often more of a safety issue than a question of authenticity.
Read more about this topic: Authenticity (reenactment)