Replacing small cassette sprockets with spacers

[Bobbybobson]

As per the title, I'm wondering if there is any problem replacing the smallest one or two sprockets with spacers, provided the lockring tightens sufficiently onto them. The reason I ask is the smallest sprocket has grooves into which the cassette lockring, which also has the grooves, bites. Will a spacer, which does not have the grooves, cause the lockring to come undone over time? I'm guessing 'no', since there's very little rotational force being applied to the lockring but I'm not sure if anyone has tried and faced problems due to vibration undoing it or anything else.
Thanks and Merry Christmas