One thing I've seem to have noticed, is credit card companies dislike when people just barely squeak by spending limits to get a bonus. Ie - they aren't interested in just your $4k spend in 3 months, but do that to limit payouts. Perhaps the real spending limit for a free guest is well under $75k, but not advertised. It can be whatever they want it to be. Let's be real, customers spending $25-$50k are also incredibly valuable for AMEX.