Comparison of two ways to check for bad data in a method

twoWaysToTestVars.js

//------------------ Option A: Use if else to avoid execution of bad data

	// panelData = {
	//		title: "a title for the panel (optional)"
	//		subtitle: "subtitle for the panel (optional)"
	//		contents: "panel contents (required)"	
	// }
	_addPanel = function (panelData) {
		var $panel
		,	panelPos
		;
		
		// Verify the integrity of the panelData
		if (!panelData || !panelData.contents) {
			log.error(_me + ': can\'t add a panel without a data object that has .contents');
		} else {
		
			// Add the panel to the dom and track it in memory
			$panel = $(tmpl(panelTemplate, panelData));
			$panel.css('width', _panelWidth);
			_configureRandomPanel($panel.find('.panel'));
			_panels.push($panel);
			_$panelBox.append($panel);
		
			// Record the panel position in memory
			panelPos = _calculatePanelPos(_panels.length - 1);
			_panelPositions.push(panelPos);
		}
	};



//------------------ Option B: Use return to avoid execution for bad data

	// panelData = {
	//		title: "a title for the panel (optional)"
	//		subtitle: "subtitle for the panel (optional)"
	//		contents: "panel contents (required)"	
	// }
	_addPanel = function (panelData) {
		var $panel
		,	panelPos
		;
		
		// Verify the integrity of the panelData
		if (!panelData || !panelData.contents) {
			log.error(_me + ': can\'t add a panel without a data object that has .contents');
                        return;
                }

		// Add the panel to the dom and track it in memory
		$panel = $(tmpl(panelTemplate, panelData));
		$panel.css('width', _panelWidth);
		_configureRandomPanel($panel.find('.panel'));
		_panels.push($panel);
		_$panelBox.append($panel);
		
		// Record the panel position in memory
		panelPos = _calculatePanelPos(_panels.length - 1);
		_panelPositions.push(panelPos);
		}
	};

I am looking for opinions on whether it's acceptable to do an error check in an if and return out of it. I recall the traditional CS wisdom is to only return at the bottom of the method, but it seems cleaner to exit on error in line.