Plus essentially worthless during event
On my 2 mile walk to work this morning I did catch 25 pokes... out of 97.
Rock event was rough on the Plus but this one is exponentially worse. Still, I'll take an event like this any day
Answers
It stinks that the Plus isn't very useful for you right now. However playing the game normally while using berries, great and in some cases ultra balls and getting amazing xp bonuses is great. And if you have a lucky egg active, hatch a few eggs, the xp boosts are even better. I feel that since a lot of the fire & ice pokemon like Swinub, Charmander, Cyndaquil are tough to catch normally, the plus makes it nearly impossible. As long as you have a lot of pokeballs to go through, keep using the Plus. But I think that this event is meant for everyone to play the game on their phone since we get bonuses for first throw catch, excellent throws, curve balls, nice throws. Most of which you don't get with the Plus.
Last night I somehow managed to allow my go plus to catch pokemon while simultaneously catching pokemon on my phone. It WAS AMAZING, especially with the event on at the moment. I don't know how it happened, may have something to with the timing of catching a Mon/spinning a stop while connecting the pogo+, or perhaps turning the location on and off... This needs investigating ASAP!