Mark,

If you are going to attend sessions you should order something. It does not have to be alcoholic. You could get a cup of coffee, pot of tea or a mineral (soda) - I like Club orange. There are plenty of teetotlers in Ireland so you won't be looked at as weird by ordering something non-alcoholic. Note that cider in Ireland is alcoholic.

The only reason you would be ordering a "round" of drinks for those around you would be it you were all together as a party. Each person would take a turn. But since it will only be you and your wife I doubt if that will apply. Sometimes patrons of the pub will order drinks for the musicians if they are playing for free or as a token of appreciation. But, once again, this is like tipping - entirely up to the individual and not expected.

Although there are some firm trad sessions such as O'Connors in Doolin and Cruises in Ennis, most are more impromptu and not publicized way ahead of time. It is best to ask around, take a walk through town looking at the windows of pubs where sessions will be posted.

Michele

No harm at all in none alcoholic drinks in Irish bars and there will be lots going on leading into St Pat's week and your hosts will likely know where the local sessions will be going on. Brogans might be worth a look whilst in Ennis they generally have something on 3-4 times a week.

My wife RARELY takes a drink and I do all the driving, so seldom imbibe, but I've NEVER been even looked at askance when ordering Cokes or tea .

Just know, that the PRICE of that tea or soft drink will probably make you THINK that you bought alchoholic beverages ...  .

It's best to arrive early and secure a seat close to the music, 'cause it can get QUITE noisy ...  .

In Ennis, opposite Cruise's is a newly built (or substantially rebuilt)  pub that often has music. 

Bob