Let's do the math, shall we?
A roughneck in Beaver County is making $15-22/hr base. let's shoot for the middle and pick $18.50 'cuz it's in the middle.
The contract is for 40 hours of regular plus 16 of OT. So your weekly is 40 (times) $18.50 (plus) 16 (times) $18.50 (times) 1.5 = $1184 a week. The article lists benefits and per diem and all that shit but they can't dock that if you don't show up for a day.
Let's say you sit out the trump rally. Your pay is now 40(times)18.50. You're never going to hit overtime. You're at $740 for the week, which means your paycheck is $444 lighter.
There are 2400 of you.
Your union is probably making about 20% of your wages because that's how it works - so each and every employee is costing Shell $528 for the day. Shell is spending $1,257,600 to have a bunch of Union guys show up at a rally.
Nice work if you can get it.