I honestly think that if it is ever done it should be possible in this manner:
Have a FP reserve where "recovered" FP go. They end up there in the following manner:
1. Self-Recovery.
Loose x% of the FP contributed and the balance goes into your FP reseve.
2. GB is razed by its own.
All FP contributed goes to your reserve.
The FP Reserve can only be used when selecting how many FP to donate to a GB.
I get that FP contributions are always a gamble but I have seen inactive players continue to have their GB's level up because other people just wanted the rewards. I have also seen daily players up and raze their entire town with no warning. I personally have lost almost 3 weeks worth of FP from that and I am much more vigilant about it now - I keep contributing until it levels, I don't care if I put in all of the points.
Spoiler: SIMILAR TO AN ALREADY FORWARDED IDEA GB: REMOVE GBs no longer wanted/needed or from players who are inactive from GB list
Contribution List: Hide/Remove Players - SFM-OVERTYPE's Idea
I think a 'hide' option