It's not the trusted sites that are the problem - but things like "Drive By" infections - especially when on public Wifi systems can do all sorts of things without you having to download or INSTALL ANYTHING. Even on a properly protected Windows system a computer can become infected with this type of attack.
There isn't as yet any decent real time A/V protection on Android like Windows 7 / W8 has.
I Re-iterate -- Internet security on a smart phone when using public Wi-Fi systems is either a joke or totally non existent - and it's even more risky now with Banks saying the CUSTOMER has to prove that they've been defrauded rather than before where your money if it was removed from your account by transactions you didn't do was paid back pretty quickly.
This has NOTHING to do with trusted sites or reputable places to shop from.
I'm really surprised that the whole discussion about firewalls and A/V protection on smart phones hasn't come up before.
(When using the phone in "Data mode" via the telecom company - you usually get better security although even here it's not fool proof as recent on going Court cases in the UK have shown where journalists were alleged to have hacked into private mobile phone communications -- my main concern is with using a browser on public Wi-Fi networks like in a Bar etc).