I think it's important to recognise that the marriage of a British female to a German citizen did not result, historically, in her losing British Citizenship under British Law, but rather in her acquiring alternative German/Reich Citizenship on marriage under German/Reich Law until 1953. However, German women did automatically lose their German Citizenship (until 1949) if they married 'foreigners' even if that meant they then became Stateless. See the following:
"German citizenship can be acquired or lost through marriage. These rules have changed over time and are affected by a number of factors.
Acquisition of German citizenship:
- Prior to April 1953: A foreign woman acquired the German citizenship through marriage to a German citizen husband.
- April 1953 until 1969: A foreign woman, who married a German Citizen husband, had a right to acquire German citizenship. If the marriage occurred between 24 August 1957 and 1969 the foreign woman could acquire the German citizenship through a declaration.
- Since 1970: The husband or wife of a German citizen could be naturalised by residence in Germany for a period of 3 years.
Loss of German citizenship:
- Prior to 23 May 1949: a German woman lost her German Citizenship through marriage to a foreigner, even if she would otherwise be stateless
- 23 May 1949 to March 1953: marriage to a foreign citizen only caused loss of German citizenship if the woman was not left stateless
- Since April 1954: marriage to a foreign citizen does not affect the nationality of the spouse. Where a party marries in a country other than the country of their personal law, then the marriage must be recognised by both countries. There are a number of factors that need to be respected, such as being of appropriate age and avoiding obstacles that would render this marriage invalid, such as being already married and being related to each other."
Source: http://www.passportia.org/citizenship/germany/marriage/
I believe that it's important to make these distinctions, as it goes someway to recognising why a woman married to a German, but living in Great Britain at the outbreak of hostilities, might have been considered a potential threat; and therefore being treated as an 'enemy alien', having married and thereby having knowingly acquired/accepted 'German' citizenship. Please note, I make no judgement on the rights or wrongs of whatever decisions were taken historically. - It's just that facts are facts; and judgements we might make now, is not the same as living with events in our ancestors time. Then again, are the decisions our ancestors had to make in a time of War that much different to the judgements/actions we expect the authorities to pursue now about who in society might present a security threat to the UK?
Mervyn