Initially proposed by Jeremy Rubin, this idea revolves around replace-by-fee-rate (RBFR) with a set minimum fee-rate ratio, aiming to mitigate significant transaction pinning attacks, specifically Rule 3 pinning related to ANYONECANSPEND transactions for confirmed outputs. Despite concerns regarding denial-of-service (DoS) attacks, it's argued that RBFR does not exacerbate the situation significantly beyond existing free-relay attack vulnerabilities. Currently, RBFR is operational on Libre Relay nodes within the mainnet, suggesting a degree of resilience against these hypothetical attacks.

The implementation of this mechanism, particularly through a soft fork, is anticipated to unlock new smart contracting possibilities beyond the initial scope of boosting or sponsorship functionalities. An illustrative use case involves Ark utilizing this mechanism to refine their connector output scheme, whereby the service escalates transaction fee-rates in return for the majority of funds over the Lightning Network (LN), requiring only the cost of an additional ~32 bytes from the sender. This approach, however, presents challenges in coordination when involving multiple parties. The broader application of this mechanism could address various issues simultaneously, though the motivation solely based on fee payment may be insufficient.

Concerns have been raised about facilitating third-party interventions in transaction mining, potentially disturbing systems like OpenTimestamps by allowing outdated timestamp transactions to be mined with minimal financial outlay. While this risk exists, the adoption of such mechanisms could significantly benefit projects like Ark, underscoring the argument that the advantages outweigh the potential drawbacks. Further details on these considerations can be found on Peter Todd's website.