The tax exempt issue has nothing to do with eligibility for a gov rate room. Tax exemption for government rate rooms differs state-by-state with different procedures and policies by state.
Rule number 1 with government rates: Always read the rate rules!
Marriott appears to have recently (within the last 6 weeks) instituted a small but significant change in the government rate rules across most (or maybe all) of their properties. Here's a sample of the updated rules I'm finding across multiple properties:
- Non-Commissionable Rate
- US Government (GOV) Per Diem rate:
- - Rate is based on the current applicable Federal government
- (govt) Per Diem rate, and subject to increase if the US General
- Services Administration increases the applicable Federal govt
- Per Diem rate before or on the guests arrival date.
- - Please refer guests to www.gsa.gov for details.
- - Available to US Federal govt and active duty military only.
- - Limit of two rooms per night.
- - Only eligible to government employees on official business
- - Must show valid Federal Govt or Military ID at check-in.
- Valid ID consists of:
- - Federal Govt issued Visa, MasterCard, American Express
- or Federal Govt picture ID (CAC or Common Access Card)
- - Military picture ID or govt/military Travel Orders
- - Federally Funded Research Development Corp (FFRDC) ID
- - Canadian Govt or Military issued ID or credit card
- - Native American Tribal Government ID
- - If no valid ID, rate will be increased to best available rate.
- - Govt Contractors, including Contractors working on govt Cost
- Reimbursable Contract, are not eligible for the US govt rate.
- - For reduced per diem requirement on stays longer than 30
- days, please check in advance whether the hotel will
- accommodate such rates or not.
(Bolding mine)
The caveat about "Only eligible to government employees on official business" is the big change from the prior rules. Previously most properties would allow government employees to use the gov rate for leisure trips (while not on official travel). This policy seems to have changed, and is likely what the front desk agent was referring to when they mentioned the "big meeting". Note that this change aligns with Hilton's policy which also typically restricts gov rates to travelers on official business.
However, the front desk agent also seems to be misinterpreting the rate rules about the use of the government issued CC. The rules for the government issued CC have always stated:
Valid ID consists of: Federal Govt issued Visa, MasterCard, American Express or Federal Govt picture ID (CAC or Common Access Card)
The reason for the "or" clause is simple: Not all government employees or military members carry a government CC. At my agency a person generally needs to travel more than 4 times a year before they'll be required to get the CC, so there are plenty of government employees staying at Marriott properties on legitimate government business without using a gov CC. This is where the front desk agent got tangled up...
OTOH, based on the OP describing a "written authorization" for a government rate it sounds like they are a contractor rather than a gov employee. Unfortunately for the OP, in this case Marriott's gov rate rules have had the
"Govt Contractors, including Contractors working on govt Cost Reimbursable Contract, are not eligible for the US govt rate" clause in them for many years. As mentioned by others, a lot of properties will overlook this restriction, but it is legitimate for a property to deny the government rate to a government contractor. The government also routinely issues CAC IDs to government contractors. These IDs clearly note that the holder is a contractor (not a government employee), so simply having a CAC does not confer eligibility for a gov rate room.