I timed my estimated 30 seconds last night after reading here (actually i got DP to time me 4 times while i did the various things i might do, and he averaged them for me). My longest was 23 seconds, my average was 19 seconds. So for some of us the 30second thing is because we're counting too fast in our heads! :)
I definitely think if a person isn't comfortable with this they shouldn't do it, though i personally am comfortable doing so. None of us is immune to tragedy, and bad things can happen no matter what. I don't feel i take undue risks (others may disagree) but despite that i know bad stuff can happen. I do think a lot depends on our kids and the layout of our houses too - i've only had one 20month old so far (DD2 is 11months). And she happened to be a physically capable, happy in water, LOUD bather, so my 30 (19?) seconds out of the bathroom she was singing away the whole time, i could hear she was fine, plus we had taps she couldn't turn on, a full bath mat to help prevent slips and a "non-slip"(she slipped a lot) rubber floor (she fell often, never got a bruise). The house we live in now has a stone flagged floor and the dryer (which was 5 yards from the bath in my teeny apartment) is downstairs, out the backdoor and in the garage here - no WAY would i fetch a towel from it here with the kid in the bath!
BTW - the whole discussion about getting towels (or not getting towels) makes me wonder - do you all have fairly big bathrooms? No bathroom i've ever had had a closet in it, and the one in my teeny apartment was small enough that on at least 3 occasions my DD grabbed my carefully warmed and brought-in-before-bathtime towel and dragged it into the bath! Needless to say, i had to fetch another! :)
We all have different lives and we're all working within our personal comfort zones as loving parents. We all have different approaches to things like this, i find it interesting and humbling to hear how different other lives are.