Sounds like an attempt to improve security. The idea behind this is not as stupid as it sounds at first, but considering all this is simply backed up by anti-virus software makes it stupid again. Anti-Virus software is usually actually pretty bad and if someone wants to hack into a company by using one of those laptops, then it certainly won’t be a malicious program that is so easy to detect even anti-virus software might catch it. Real malicious software by real paid hackers, who do this for a living, know all the ways to obfuscate their program from any anti-virus software in the world. For example, it’s even easier and totally safe to use a non-malicious software to achieve malicious goals. This is why the Word Editor macro attacks were so popular and probably still do some pretty nasty job, even though there is now always a huge warning telling the user, he shouldn’t open macro enabled documents from random idiots.
So, in conclusion, having the idea of using your laptop daily anyway, which makes the 4 weeks really generous, and force everything through a VPN, etc. is not a bad idea. But having this idea based in practice on anti-virus software makes it still stupid.