EtG formation outside the liver
No, because the equilibrium for the simple reaction lies on the side of the reactants:

$$\ce{Ethanol + glucoronic acid &lt;&lt;=&gt; Ethyl glucuronide + H2O}\tag{1}$$

The reaction works enzymatically inside the cell because glucuronic acid first reacts with UTP, turning it into a mixed anhydride (phosphate of UDP bound to carboxylic acid of glucuronic acid) plus inorganic phosphate.

$$\ce{UTP + glucoronic acid &lt;=&gt;&gt; UDP-glucuronide + phosphate} \tag{2}$$

Then, the enzyme swaps UDP for ethanol or other molecules. 

$$\ce{Ethanol +  UDP-glucuronide &lt;=&gt;&gt; Ethyl glucuronide + UDP}\tag{3}$$

The net difference between hypothetical reaction (1) and the two step process (2) and (3) is the hydrolysis of UTP, a reaction with a negative Gibbs energy of reaction (i.e. equilibrium constant larger than one):

$$\ce{UTP + H2O -&gt; UDP + phosphate} \tag{4}$$

So the formation of UPD and phosphate from UTP drives the two step reaction (it is a coupled reaction).

Attaching glucuronic acid makes molecules more water-soluble, helping to excrete them in the urine 1.