Good Restful design: different payload for different accounts for same url

Question

Is it considered bad design if one url accepted different payloads depending on the basic authentication used? for instance:

http://localhost/userA PUT by userA is allowed up pass XML_A but

http://localhost/userA PUT by adminA is allowed up pass XML_B which is XML_A plus more.

in otherwords it is the same resource but what can be updated is determined based off of the credentials supplied.

I have seen conversations about return data but not too many about request payloads. (not sure if it would be considered different) thanks

UPDATE

Based off of Darrel Miller information, would the following be a better design?

GET /{Username}       readonly resource returns different payload based off of rights
GET /{Username}/UpdInfo  returns only updatable info (subset of GET /{Username})
PUT /{Username}/UpdInfo  updates info 1 to 1 from the GET /{Username}/Info

GET /admin/{Username}/UpdInfo returns updatable info (larger subset of GET /{Username})
PUT /admin/{Username}/UpdInfo updates info 1 to 1 from the GET /admin/{Username}/Info

Answer 1

The problem I see is that PUT method replaces the entire contents of the resource that is targeted. e.g if the following sequence occured,

PUT /UserA  with  XML_B

PUT /UserA with XML_A

GET /UserA returns XML_A

UserA no longer contains the extra information contained in XML_B.

It think you would be better to just represent the two different sets of information as different resources:

GET /admin/UserA

PUT /admin/UserA with XML_B

GET /UserA

PUT /UserA with XML_A