careful with his leg

anti-exploit is not an excuse, although I understand that angle of it. Major ad networks allow such URLs and they're dealing with massive traffic and advertiser bases...

Ok - So - elaborate on what other methods of testing can be applied!
As far as banners are concerned it's about running several at a time that alternate to gauge the CTR rate.

I've come across posts from mainstream affiliates who posted their test results - and they tested page layouts and colors not just their creatives. Sometimes it's downright shocking to see how much improvement there is over what they previously used.

Of course I used to think you just put up a banner and let it rip until I read stuff.

Nowadays I won't be caught dead using just one banner hoping it will rain money especially on a $2k spend