Prompt barge-in-after feature for postponing barge-in ability?

[chewi]

Testing of our newest service found that entering too many digits for a prompt caused the following prompt to accept those digits as a barge-in before anything is heard. An artificial delay is undesirable and a totally unbargeable prompt in-between may not always be appropriate so it would be useful if prompts could postpone the ability to barge-in after a given amount of time. What do you think?