The functionality you requested was already present by setting a player's bhop multiplier to -1.0 . I understand however that this is a really inconsistent way of handling things, so I've updated the plugin for your request

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I'm not able to test the plugin myself at this point in time, but it should work. Give it a whirl, if it doesn't work tell me. Otherwise I'll update the main post in a few days with this new version.
changelog
Code:
* Bhop multipliers are now limited to being larger than or equal to 0.
This in effect removes the functionality that a multiplier of -1 disabled bunnyhopping on an individual
* Added new admin-cmd: sm_bhop_enabled , which allows admins to disable bhop on individual players.
Usage: sm_bhop_enabled <target> <0/1> . Ex: "sm_bhop_enabled thaCURSEDpie 1"
EDIT:
And yes, that should disable the bouncing. Have you given it a try?
EDIT:
Don't use this version, it contains a breaking bug, which is fixed in version 1.0.4.