You raise a valid point, to wit, that the penitential nature of these two days ought not to be compromised.
However, there are a couple of points:
• Church law does define Ash Wednesday and Good Friday as days on which Catholics must fast, but not all Catholics. Only those aged 18-59 are obligated to fast, and even then, those whose health would be seriously injured by a strict fast are allowed to consume as much food as necessary.
Growing up, I remember Mother Angelica on EWTN commenting to callers who had been away from the sacrament of reconciliation or were afraid to go that they would feel so good afterward, that they should go out and buy a pizza. Such a comment came from a heart that had approached the sacrament and found peace in the deep mercy of God.
We can trace the use of bells in the liturgy back to the liturgy of the Old Testament. In the Book of Exodus, the vestments of the high priest are described in detail. Among the ornamentation on the vestments are alternating pomegranates and bells (Exodus 28:33-35).
God instructed the bells to be sewn on the vestments for two reasons.
1) They were part of the joyful noise made to the Lord, as referenced in Psalm 98:4.
Whenever we speak about handling the Eucharist, we desire to treat the Lord with the greatest respect. Even with this most important desire, there will be unexpected situations that will arise. How do we handle these situations while keeping respect for the Blessed Sacrament at the fore?