What is the ruling on using a widow's discount card for taxis, when it is in the widow's name, but someone other than the widow uses it?

If the government provides your aunt with a discount card for using a taxi, this discount is specific to her, and it is not permissible for anyone else to benefit from it, because it is a conditional gift. Devising a trick to obtain this discount is forbidden and constitutes unjustly consuming people's wealth. What makes matters worse is that it might lead your aunt into lying, deception, and breaching the contract, all of which are forbidden actions. This act is forbidden and will cause both of you to fall into sin.