This can really be a fun way for children to get familiar with the language.
If we think of how 30- 40 years ago those schoolmates/colleagues of ours who spent 10 days or two weeks in a “pioneer-camp” spoke Romanian more easily than those who did not, just because they were in an enjoyable environment where that language was the only way of communication, it is not difficult to imagine how a summer-camp could help children use the new language more willingly.
And just imagine the experiences, the buzz they will have.