Wildcard character for Subscriber attributes

[ravi-prakash-v]

When a subscriber wants to operate in all domains, or in all cities, should we use the wildcard character * in the field instead of leaving it blank or null?

For example,

{
    "domain" : "mobility",
    "city" : "*",
    "country" : "IND",
    ...
}

represents a Subscriber that operates in all cities across India.

[venkatramanm]

Not passing the attribute 'city' is enough. Leave how it's persisted or handled to registry implementations.