I'm sure kbrkr meant grace note, not trill. However, the Floyd Cramer style that we're all familiar with, incorporates what's called a hammer, or slipnote technique... similar to, but slightly different than a grace note.
Where a grace note slightly precedes the beat, the FC slipnote is on the beat and played with the third above, major or minor, depending on the chord inversion and melody note. Also, a grace note is usually a semi-tone below and the country style slipnote is usually a whole tone below.
I've been incorporating FC styling almost as long as Floyd himself... since the 60s. Not only has it become a staple in country piano, you'll hear it in many other piano styles, including R Hornsby and most recently N Jones. Quite a long lasting influence.