Most states define it as charging inflated prices during a crisis or emergency, not simply raising prices beyond what geraldyo thinks is reasonable.
Wikipedia: "Price gouging occurs when a seller increases the prices of goods, services, or commodities to a level much higher than is considered reasonable or fair."
edit: updating with proof, Texas state definition is "selling or leasing fuel, food, medicine, or another necessity at an exorbitant or excess price, or demanding an exorbitant or excessive price in connection with the sale or lease of fuel, food, medicine or another necessity."
https://www.in2013dollars.com/Food/price-inflation/2108-to-2...
then there's the question of does the union have any real leverage, which varies a lot by industry and trade. ufcw for example has failed both in securing real wins for grocery workers AND in pushing against price gouging by grocers
after being failed by nationals (for me it was usually cwa), tried going more wildcat but iww are just as ineffectual for different reasons, then got involved in the co-op space but groups like usfwc are just as ineffectual for still different reasons
edit: for proof here's how Texas defines it per https://www.galvestoncountytx.gov/our-county/district-attorn...:
"selling or leasing fuel, food, medicine, or another necessity at an exorbitant or excess price, or demanding an exorbitant or excessive price in connection with the sale or lease of fuel, food, medicine or another necessity."