I realize this may sound too Catholic for some, but I think one's salvation is tied to it, in a qualified sense.
The Lord's Supper doesn't save; the Gospel does, and the Gospel alone, being the power of God, is what saves.
But take note of what it means to be ex-communicated according to the Scriptures: it means to be "out of communion".
Someone who has legitimately been removed from the body of believers because of any of the sins listed in
1 Corinthians 5 (e.g. fornication, drunkenness, blasphemy, covetous idolatry, etc.) is turned over to Satan.
Consider then what Jesus said in
John 6 and in
Matthew 18. The bread and wine doesn't do the saving, but they are hallmarks that one is saved, and being denied access to the communal meal
for legitimate reasons means one has not only lost their fellowship with the saints of the church, but also their fellowship with the head of the saints of the church.
There is no salvation outside the Body of Christ. And for a member to fall into grievous, unrepentant sin, and so be removed, not only from geographical proximity, but also from the meal of the Lord's Supper (a la Judas), means that, unless God grants them repentance, they are lost (just like the son of perdition).
Take into account the "spots on the feasts of charity" mentioned by Peter and Jude. Such people, if allowed to partake, actually ruin the supper and cause dangerous problems to the Body of Christ.