Declined with the following reason: elements are styled through CSS cascade. In order to handle that you can override explicitly RadFormDecororator's styles. For example:
CSS:
	<style>
		@media screen and (-webkit-min-device-pixel-ratio:0) {
			.RadForm.rfdCheckbox input[type="checkbox"].rlbCheck,
			.RadForm.rfdCheckbox input[type="checkbox"].radPreventDecorate,
			.RadForm.rfdCheckbox input[type="radio"].radPreventDecorate {
				width: 13px;
				height: 13px;
			}

			.RadForm.rfdCheckbox input[type="checkbox"].rlbCheck,
			.RadForm.rfdCheckbox input[type="checkbox"].radPreventDecorate {
				-webkit-appearance: checkbox;
			}

			.RadForm.rfdCheckbox input[type="radio"].radPreventDecorate {
				-webkit-appearance: radio;
			}
		}
	</style>
ASPX:
	<form id="form1" runat="server">
		<telerik:RadScriptManager ID="RadScriptManager1" runat="server"></telerik:RadScriptManager>
		<telerik:RadFormDecorator ID="RadFormDecorator1" runat="server" DecoratedControls="All" Skin="Silk" />
		<input type="radio" name="radio-set" id="Radio1" class="radPreventDecorate" />
		<input type="checkbox" name="checkbox-set" id="Checkbox1" class="radPreventDecorate" />
		<telerik:RadListBox ID="RadListBox1" runat="server" CheckBoxes="true">
			<Items>
				<telerik:RadListBoxItem Text="item 1" />
				<telerik:RadListBoxItem Text="item 2" />
				<telerik:RadListBoxItem Text="item 3" />
			</Items>
		</telerik:RadListBox>
	</form>