How do you guys know these trezors and ledgers aren't getting intercepted in the mail and their guts stuffed with something else?
The Ledger is designed in a way that, if tampered with, then it won't work and it becomes obsolete. Basically the Ledger itself is tamper-resistant, so there's no need for tamper-resistant seals on the packaging. Don't know about the Trezor through as I haven't read much about it.