Why does the entry cost increase in Tractor Pulling?

To keep the competition balanced, the cost of entry changes based on how often you participate:

First Entry: Your first entry each day is Free.

Additional Entries: If you choose to enter again, the cost will increase with each submission.

Reset: This cost resets back to free every 24 hours.

Why is this?
Since Tractor Pulling events are always live and not restricted to specific time frames, this scaling cost discourages spamming entries.