You can't download the blockchain if you're not at home, and clients like Multibit rarely works in hotels. Wifi's free but they have firewalls and routers which blocks most ports. Same with Mycellium on my tablet.
Thats not true, Electrum would work everywhere and even if you can't connect it, you can always make a transaction using it, sign it and then broadcast it using any broadcast service such as, https://blockchain.info/pushtx, https://blockr.io/tx/push.
Your coins still remain safe and secure in your wallet.
Have you tried it in many places? Because the way I see it, it's getting worse and worse. There are more and more places with, as they say, free wi-fi, but you can't send emails because port 993 is blocked, you can't do FTP and all BTC software is blocked. Anyway the solution you propose isn't much useful, because it only allows sending, not receiving, so you would have to connect regularly to synchronize what's on your computer with what's in the blockchain.