[citation][nom]eeide[/nom]Even if Apple recalls the iPhone 4 because of the antenna issue. I wouldn't send mine back! I have yet to experience any issues. The time and hassle of sending it in, getting the new one, setting all back up just isn't worth it to me unless I start having problems. I actually intentionally cover up the bottom left corner all the time because I'm still in my 30 days and can take it back if it starts acting up. I personally don't like cases on my phones, so I wouldn't even consider a bumper if I have issues.[/citation]
A "recall" doesn't necessarily mean you have to send it back for a new one. It might just mean you bring it into any Apple store or authorized vendor and have your free bumper put on it. If you don't want a bumper, they may have another option such as a laminate coating or something.
Just like if a car company does a recall on a certain model of car, you don't bring the car back and get a new one, you bring it in to the dealer at your convenience and they fix the problem or replace the part at no cost even if your particular model didn't have said problem.
If, however you refuse the options they give during the recall, they are not obligated to give you a refund or a new iPhone 4GS replacement (when it's out). If you did get such a thing, it's because you're exceptionally good at bitching.
Since there is no iPhone 4GS out at the moment or that will be out any time soon, and the problem doesn't completely break the phone, you're unlikely to get any kind of replacement during a recall.