experience with Train strikes in Italy

I got a similar alert here in Milan but I am only going to the airport.
Your only option if the worse comes is to be aware of your options and be prepared to take the bus from Ventimiglia to La Spezia and then a taxi to Vernazza
http://www.lirosilinee.com/portale/

The transit strike starts now…9 pm tonight to 9 pm Friday. Regional train service is guaranteed at rush hours (6-9 am and 6-9 pm). Not every train will run but enough to get people where they need to be. Outside of rush hours, it’s likely to be a much longer wait. So if you have some flexibility in your plans, target rush hours, after 9 pm or wait until Saturday morning.

And pack your patience…it’ll likely take a bit of extra time but you’ll get there. It’s also going to be scorching hot tomorrow, pack water along too.

It looks like they were partially bluffing; all of the trains were running from Milan. There were no major disruptions after 9am.

I don't know who "they" are in your mind, but workers are free to take part in strikes or not. Striking is not mandatory.

What Milan's workers did on May 20 could have no relevance somewhere else at another time.

LOL I know I am part of a union also. The trenitalia ap kept warning me to consider my options so I don't miss my flight today.

"Striking is not mandatory"

Yeah, it's pretty easy to blow it off as no big deal, but when a strike is called no one knows the actual extent of the strike re: areas officially cited against areas actually affected. I've been caught up in both the "NOW what" to the "hey looks like we're good to go."

Off course the strikes are called when they have the most impact, I've also noted that Italians never strike on weekends, no point in spoiling one's time off. So need ASSURED major train travel always book it on Saturdays and Sundays.

Personally I loathe work to rule strikes, anywhere.

Always book the earliest mode of transportation if you absolutely need to be somewhere has just been my experience traveling in Italy.

There used to be and maybe still is a website that showed all the upcoming transportation strikes in Italy both nationally and regionally, I just can't seem to find it right now.

Here it is - https://www.commissionegaranziasciopero.it/

that Italians never strike on weekends

If Italians are "train workers", they do not strike on weekends because on weekends there would be zero guaranteed trains. They could even legally block the Malpensa Express and the Leonardo Express without being fired. In short, a train strike on the week-end would be like dropping an H-bomb and no Union (but Trenord's), has ever done it.

Other Italians do not strike on weekends because being on strike when you are not supposed to be at work anyway would be a little odd.

Be flexible and minimize your baggage but you probably have this covered.
After 3 days in CT staying in a B&B in Levanto and using local trains that would occasionally not arrive due to a strike, we were going by train to Lucca changing trains in La Spezia. But as part of a rolling strike, the train from La Spezia to Lucca was cancelled which we discovered in La Spezia. So find the bus terminal, find where to buy bus tickets, line up and get onto a bus with a number of us tourist with baggage piled up in the aisle. Next problem was that the bus dropped us off in the centre of Lucca and our hotel was near the train station so we had to find our way through the old town. Just relax and experience Italy. ps it was raining on and off, light showers.
We were then, after 2 nights and 1 perfect day in Lucca, going by train to Siena which ran as scheduled. No further train problems Siena / Florence / Turin.