A good question & an interesting topic.
Intraspecific aggression can play a part. Not rough sex, but more frequently in (competing) males. There might even be social structuring, with tail loss occurring more readily in subordinate individuals. A price the species pays for the fittest males producing most of the progeny, I guess.
In European species, I seem to remember that in
Euleptes europaea intraspecific causes cause for a high portion of the populations to feature a regenerated tail.
This is a very nice paper on the subject.
http://ftp.eebweb.arizona.edu/courses/E ... 202009.pdf