A few comments may be in order. Some of the last words of Jesus to his followers were: “Go ye into all of the world and preach the gospel…” (Matthew, 28:19-20)
This command His followers have sought to fulfill through the centuries until the present time. Jesus also said it should be shared with “whosoever will.”
Nobody is compelled to believe. All of us are exposed to a variety of beliefs, so if a message does accompany the shoeboxes, the person receiving it can accept or reject it. Let the love of God be proclaimed wherever and to whoever.