  Financial exchange operators cater to the needs of their users while
simultaneously ensuring compliance with the financial regulations. In this
work, we focus on the operators' commitment for fair treatment of all competing
participants. We first discuss unbounded temporal fairness and then investigate
its implementation and infrastructure requirements for exchanges. We find that
these requirements can be fully met only under ideal conditions and argue that
unbounded fairness in FIFO markets is unrealistic. To further support this
claim, we analyse several real-world incidents and show that subtle
implementation inefficiencies and technical optimizations suffice to give
unfair advantages to a minority of the participants. We finally introduce,
{\epsilon}-fairness, a bounded definition of temporal fairness and discuss how
it can be combined with non-continuous market designs to provide equal
participant treatment with minimum divergence from the existing market
operation.
