Detecting smartphone/tablet browsers that support cookies and jQuery Mobile

I have a website with a full browser and jQuery Mobile interface and users can switch between the two. Their preference is stored in a cookie. By default the site serves the full version to visitors whitout a preference cookie, but to make it better for modern smartphone users I want their default to be JQM. So, I have this code in the constructor of my base controller class:

class BaseController
{

    protected $mobile;  // must be 0 or 1, cookies can't handle boolean 'false'

    public function __construct()
    {
        if (isset($_COOKIE['mobile']))
        {
            $this->mobile = $_COOKIE['mobile'];
        }
        else
        {
            $this->mobile = $this->isSmartphoneWithCookies();
            setcookie("mobile", $this->mobile, time() + 7776000, '/', ''); // 90 days
        }
    }

    private function isSmartphoneWithCookies()
    {
        $SMARTPHONE_WITH_COOKIES = "android.+mobile|blackberry|ip(hone|od)|opera m(ob|in)i";

        return preg_match("/$SMARTPHONE_WITH_COOKIES/i", $_SERVER['HTTP_USER_AGENT']) ? 1 : 0;
    }

    // the rest of my controller class....
}

Here I prefer speed to accuracy, so I am not looking for a slower, up-to-date lookup service as suggested here: Simple Smart Phone detection

Just a quick indication that the visitor has one of the current top smartphone/tablet browsers that support cookies and JQM.

Can someone suggest an improvement for my $SMARTPHONE_WITH_COOKIES? Or point me to a collection of UA signatures that fit my use case? Specifically, is it safe to have blackberry in the list? Am I overlooking a popular capable browser?

By design, the primary UI selector for my app is the user. I do not want to delegate that to a detection script. The bit of detection in question is just to give a clever default. It is a risky feature, because a false positive (for example a smartphone without cookie support) can make my site totally inaccessible to some users. So if it fails, it needs to fail towards the standard interface.

For what it's worth, I considered the following:

• Opera Mini doesn't have good enough javascript support for my JQM app.
• Opera Mobile running on Android is a major category that I would have loved to catch, but I am not confident enough that I can correctly pick all of that out of the UA string.
• I considered "windows phone os 7", but decided it will date too quickly
• The subset of Blackberry browsers that qualify is also too tricky to detect simply, so rather than risk a false positive, I decided to drop the whole tier.

So, what I am left with is:

$SMARTPHONE_WITH_COOKIES = "android.+mobile|iphone|ipod";

The cost of keeping it this light and simple is that I will have to reconsider this question again every two years or so. I will also have many mobile visitors that will need to do an extra click to get the mobile version.