Hotels will typically ask you upon arrival for a card to authorize a pre-set amount of funds to pay for any incidentals/damages during your stay. If there are no issues with your room upon checkout, the authorization will eventually expire. While the authorization is not an actual purchase, your Relay App balances will reflect that the funds are technically tied up.
For this reason, we recommend using a separate card for the pre-authorization to avoid any confusion. Upon check-out, if you do need to pay for incidentals/damages, you can always request the hotel to swipe your Relay Card instead to pay for the actual amount incurred.