It wasn't necessarily the king's court.
You're referring to the practice of "The bedding ceremony", which was done in many places around the world at various points in time, by many classes of people, and had two-fold purpose.
In some places, it was a show of community and family support for the union as marriages were far less 'personal' than we treat them today. By that I mean, it was not just Joe and Sally getting married; it was the Johnson Family and the Stone Family uniting together.
Many marriages were not considered legally valid until consummation. This guaranteed the marriage was legally valid, and therefore their offspring were legally valid heirs. This is likely where the notion of your question came from, as the interest in legally valid royal heirs would be significant.
I'm not sure about your reference to "King's Court", so unless you have some specific Court or period of time to point to? This practice seems to have died off by the 17th century.
EDIT: My source - "Marriage Customs of the World" by George Monger
Which king?