IANAL, but I have created eLearning materials on GDPR based on the advice of subject matter experts who were.
I suspect that the answer is probably no, users aged 13 - 16, who are based outside of the European Union (EU), probably cannot use SE while travelling to an EU member state.
It is my understanding that while in the EU, you will be subject to the General Data Protection Regulation (GDPR).
Any changes to personal information while there would therefore be covered by those regulations.
Article 8 of Chapter 1 of the GDPR states that personal info can only be collected from persons under the age of 16 (not just EU citizens under the age of 16) with parental consent.
Where point (a) of Article 6(1) applies, in relation to the offer of information society services directly to a child, the processing of the personal data of a child shall be lawful where the child is at least 16 years old. Where the child is below the age of 16 years, such processing shall be lawful only if and to the extent that consent is given or authorised by the holder of parental responsibility over the child.
[Point (a) of Article 6(1) simply states that:
- Processing shall be lawful only if and to the extent that at least one of the following applies:
(a) the data subject has given consent to the processing of his or her personal data for one or more specific purposes;]
SE has no way to verify that parental consent has been given, and so would - in common with most tech companies - presumably err on the side of legal caution in such cases.
You might also be interested in the related Meta:SE question: Why can't I use Stack Exchange if I'm under 13 years old, and is there any way I can use it legally?