I wouldn’t advocate “chopping” bolts where it’s feasible (i.e., where they’re not glued in) to simply remove them (in whole). If someone is lame enough to bolt a crack in the first place, they may be dumb enough to drill more holes to replace bolts that have been chopped. Bolts aren’t really that expensive, so I don’t think that the destruction of one’s bolts will really be all that much of deterrent--the lame bolter will simply buy more.