I distinctively remember someone asked this question in Sklz's thread. Dulrik responded that snare + shooting is fine. He said that he hasn't witnessed anyone to abuse this in a twink effect yet. Then he said people come up with new tricks all the time.
Here it is:
Gork wrote:
Does this include situations where skills or spells make the target helpless? For example, a scout snaring a NPC and shooting it down.
Dulrik wrote:
Not currently. Using snare is unpredictable and setting it up is fairly time consuming. As far as I know, killing snared victims for XP has never been a good method for power-levelling. I could easily be wrong though. Seems like people come up with new tricks all the time.
In short: snare + skirmish gives experience.