Ungrounded electrical outlets can result in electrocution, damage to electronics and voided appliance warranties. Homes wired prior to the mid 1960’s, were typically wired without the ground fault circuit interrupters (GFCI) common today.
If you are not sure if your electrical outlets are safe, have a qualified electrician do a safety assessment.
Renting an older camp this summer? Ask if it has ground fault interruption protection.