I agree with mouser and his idea of a minimum post restriction. But i would expand that with a minimum time restriction: You need to be registered at least one month before your signature becomes active or you even can define one. Both sanctions have the advantage that they can be scripted and don't need someone to monitor this.
Btw, there a lot of useful classes which can be very helpful. What i use very much is the Apache commons project, in particular the lang project (JavaDoc) which contains "Utils" packages, e.g. ArrayUtils which has a toObject() method that converts an int[] to Integer[].
The package that i use on every Project (when possible) is StringUtils. I coundn't live without StringUtils.defaultString() and StringUtils.isBlank().
int[] ints = new int[]{1,2,3,4,5}; Integer[] intObjects = new Integer[ ints.length ]; for( int i = 0; i < ints.length; ++i ) { intObjects[ i ] = new Integer( ints[ i ] ); }