A tennis price can have a reliable observation timestamp while the underlying match has no verified start time. Those are two different facts. Turning the capture time into the match date creates a false fixture even when the decimal odds were transcribed accurately.
The event date tells a reader when the sporting contest is scheduled or took place. The capture time tells the reader when a particular source price was observed. A price might be collected days before a match, during it, or from an archived screen later. The order and distance between those times affect how the record can be interpreted.
Suppose a record contains two named players, a competition and odds of 1.80, captured at 10:15 UTC. If the source omitted the start field, 10:15 is not a substitute. The price can be labelled as a historical observation with an unknown event date. It should not be placed into today’s tennis calendar merely because today was the collection date.
Timezone information matters for both fields. A local date with an unspecified timezone may be insufficient to place a fixture confidently around midnight. Converting an established UTC timestamp into a reader’s local time is a display operation. Assigning UTC to an originally ambiguous local time is an unsupported factual change.
A useful market record also needs the selection and period. At 1.80, inverse probability is about 55.56% before margin, but that arithmetic says nothing about whether the price concerned match winner, a specific set or another outcome. Reliable time information cannot compensate for missing contract identity.
When comparing two bookmakers, prefer observations covering the same contract at comparable times. If the times differ, show them rather than labelling one number the best current price. A historical comparison may still be educational, but it cannot establish a current betting opportunity or market availability.
This separation also improves automated publishing. Complete dated events can enter a bounded calendar. Undated records can remain in a clearly labelled research section when their participants and markets are usable. Neither process needs to invent a start date, generate a large volume of thin match pages or refresh the article date to disguise an old observation.