Mitigating fraud risk doesn't make their policy anti-consumer. They are transparent about the risks and even warn consumers to only accept gifts from people they trust.
They have server records but premium time begins to be consumed at the moment the gift is accepted. Premium time is a service rendered, not a license or some type of goods. Any matches played will have premium bonuses applied to them. If you seriously think it is practical for them to go through X number of matches and remove experience, relock unlocked modules & tanks, revert crew experience, then remove extra gained silver (nevermind if the player actually already spent their silver total down below the amount they'd need to remove), then you are seriously overestimating their manpower. You've taken a situation where they have already lost money via the chargeback and thrown more money at it, well done.
Maybe you think they could do it by storing multiple versions of your account, like Windows Restore, simple right? Just restore to an older version. Except chargebacks can be thrown on credit card transactions for 120 days up to 180 days for international after the purchase. Which means if I gifted you a 7 day premium time right now, which you accepted, then 6 months later I do a chargeback, you now lose 6 months worth of progress. Far more than you ever gained from the week of premium. Would that make you happier as the consumer than paying $10? This is totally not even accounting how much database bloat they'd experience by storing 6 months worth of back ups of 100 million+ of player accounts. Now you've given people an ultra troll situation where they can exploit to fuck over others.
Again, the burden is on the recipient to verify that the sender is somebody they can trust, WG states that repeatedly. If a chargeback happens and their account gets locked, their beef should be with the sender, not WG. This is WG setting a fair policy that allows them to prevent fraud, and doesn't result in them outright banning accounts (which would certainly cost them less in terms of employee hours, but also be worse for their customers and PR). There's plenty of things you can fault WG on and call their policies sucky and anti consumer, this isn't one of them.