When I was in Brasil last year, I attended my fiancÚe's phonetics classes at university, and there I came across the teacher using two symbols that I didn't use in a similar way as he did. Since then, I've noticed that in dictionaries, they use the same symbols as the teacher there used. I think both the teacher and the dictionaries claim to be using IPA symbols.
The first one is the one that bothers me the most. A word such as 'rat' is written as /rŠt/ in these phonetic scripts. I learned at my phonetics classes that /r/ was a voiced alveolar trill. My phonetic transcription of 'rat' would be /ɹŠt/.
Something tells me that it is some excuse like '/r/ is easier to write/type than /ɹ/' that makes this the case, but it bugs me, and I'm not even a phonetician! The point of a phonetic script isn't for convenience, it is for accuracy of writing what someone says, as they say it.
Maybe there is a reason, however. Perhaps, /r/ is /ɹ/ in some other phonetic script.
The second set of symbols that I dont really understand is /e/ and /ɛ/. In some places I have seen the word 'bed' transcribed as /bed/. To me, /bed/ is 'bade' in my own accent - Scottish, where we dont have the diphthong. It's hard to say what I think /e/ sounds like, as it doesn't occur in Standard English accents. However, a word like 'bed' I would transcribe as /bɛd/, without a doubt. Is there a reason some people write /e/ and not /ɛ/?
Similar for /e/. Strictly 'bed' is /bɛd/ in standard English, but since a true /e/ is not spoken in most Englishes, /e/ is used for /ɛ/.
/r/ and /e/ are used for phonemic transcriptions - again, on the assumption that English is being discussed, and that /ɹ / and /ɛ/ are intended.
I agree that it's done for convenience, and that sometimes the practice could lead to misunderstanding. I also agree that it's annoying for perfectionists, linguistics students, and English speakers who do use these sounds. If one is all three, I imagine it would be hard to live with!