The choir I direct, we still take an attendance, , it shows whose, dedicated,organization, and also as stated before your must attend 2 rehearsals in order to sing on Sunday Morning. Choir members have to understand that singing is a ministry and within every ministry you have to be decent and in order. Practice is always necessary and we want Him to perfect that which concerns us. so Showing up to rehearsal means that you are concerned about Him and also lives of those whom may become saved through the ministry. So God is able to come and perfect us. Practice makes perfect. Choir members need to recognize if they are on the choir for ministry or out of formality.