Technically there is no requirement that location targeting be used in conjunction with TA targeting. For Twitter Ads there are 3 service levels for advertisers, starting with Small/Medium Businesses (SMB). For any SMB service level (credit card billing only), they are required to also target a location for their campaigns. For all other advertisers, no such restriction applies. From our support center:
Note: Small Business advertisers are limited to targeting users in
countries where the Twitter SMB Ads product is available. For a list of
countries available for targeting by Small Business customers, please
reference this article.
Today we don’t expose this service level via the API, but you can derive it by checking for the types of funding instruments available on the account. If there is only a CREDIT_CARD funding source, you can assume the account is a SMB-service level and requires location targeting.