I come across so many sites that allow you to resize the text area in Safari, and quite frankly it annoys me. The feature of Safari doesn't annoy me at all, it's the way designers haven't planned for the odd user to resize the comment textbox or some other textbox, so that when it happens it messes with the whole page.
A way around it? Well, for starters ask yourself why the user wants to resize the text box in the first place. If there is a reason, you need to re-jiggle your design. If there isn't, you can use CSS to prevent the user resizing the text box, so that it doesn't mess with your page.
textarea{
width:200px;
min-width:150px;
max-width:250px;
height:200px;
min-height:150px;
max-height:250px;
}
An example of this:
Safari obeys these rules, and stops the use resizing a text box further than you've specified, thus not screwing with your design, while letting the user change the textbox size to a certain extent. Try it on my comment box below.
The thing is that Safari implemented this feature by default enabled without asking anyone, causing many existing sites to use this feature in their browser often breaking the layout. It's not a web developer issue, it was a browser vendor issue. However is good there are ways to solve this issue, and also good that we have a way to enable resizing for the textareas when we need it.