Whilst certain anagram indicators are universally accepted ('broken up'. 'rearranged'), many others are on the fringes of acceptability; generally blocked puzzle editors are more tolerant of questionable indicators such as "perhaps" than their barred puzzle counterparts. I have never used 'released' myself, but since 'relaxed' is usually seen as valid then you could certainly argue based on the Chambers definitions of the two words that it should be (just about) ok. If I am unsure about a particular indicator, I tend to go to the Azed archive at:
http://www.andlit.org.uk/azed/search2.php
and search the Azed competition clues for the word in question to see if Azed has ever allowed it - absence of a word is not a definite contraindication, but presence suggests that it is acceptable.