My guess is that the unfortunate bank with a teller that accepted such a check may think it has a technical indemnity claim, but will feel too stupid/unobservant to file it. Technically there is no indorsement if it doesn't include a signature of the indorser (although the signature can be in any form, including part of a rubber-stamp impression).
An indemnity claim is a claim. The bank on which the claim is made can refuse the claim if it feels that the claimant bank was adequately forewarned that the check was previously negotiated via RDC, and hope that the refusal will turn the claimant away. The only sure course is to have the remote deposit capture or RDC as part of the indorsement on the back of the check.
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John S. Burnett
BankersOnline.com
Fighting for Compliance since 1976
Bankers' Threads User #8