score:3
No, you're not allowed to do this, given that the card always requires a minute between validations, and there are guards at the barriers to see to it that there is no abuse.
However, if you save the original receipt, you can get the 2 lari back when leaving Tbilisi (if less than 1 month after buying the card), by presenting your card, receipt and passport at a ticket counter
Upvote:1
Seeing that the card itself costs a mere 2 lari - which is less than $1 - I don't see why you would need to share one. Simply get two (or more) cards for each person and top them up individually. A single ride is around $0.20 so it won't break your budget.