It depends on what you care about when you say "open". If you care about security/privacy and the fact that you're running potentially Trojan-infected code on your machine, then any non-open code makes a difference.
The fact you use a connection to the internet opens yiu to many nefarious means to "screw you over". I can think of subtle things like changing adservers to backbone providers, router protocol redirections, ssl master cert spoofs (care of us govt), and many others.
Unless you were the types that freaked out on mm256.dat and nsakey, use standard security and you're fine.
If you did freak out, im sure we can work out a GPS-login script that watches location, bloodtype, retinal scan, passphrase, and voice scan to get a guest account.
