There are a few individual case studies that seem to suggest it's difficult but possible.
They're far from perfect as evidence since they're self reported, but there's one case of a woman in Australia which is sufficiently detailed, seems to be independent of groups with a direct interest in advocating the technique, and contains enough caveats on the difficulties of the technique that it appears credible and has been reported as credible by mainstream media.
This write-up gives a fairly straightforward summary:
The cues she watches out for are cries/grizzling which become desperate when her baby needs to wee or poo.
"I use a combination of common sense, instinct, timing and listening to my baby," she writes.
"Often if I get it wrong and we have an accident it is because I haven’t listened. I will then kick myself for ignoring her vocal and physical cues."
"I [take her to the bathroom sink] then say 'wee, wee' and make the sound psss so this cues her to go to the toilet. If it’s a poo I say 'poo, poo'' she explains.
"I’m not sure if other people who practise EC liken it to toilet training a puppy but I think it’s very similar.
"With my puppies I would take then to the grass and tell them to wee. Now when I need them to go the toilet, for example at night, I just put them out and tell them to do wee."
...And if she ever takes too long to respond to her daughter's cues and she has an accident, Cindy makes sure to repeat the word "wee wee" so her baby knows to associate the action with the term.
There's a more detailed first-person account by the woman herself on an Australian parenting site.
Neither mentions childcare centres, but the first-person account does mention using the technique in a cafe toilet when the baby was two weeks old (with the help of "my poor husband [who] is madly cleaning up what didn’t make it into the bowl"). For those sorts of details it's probably better to ask on the dedicated Parenting site or on one of the sites that promote the practice (three are linked in the above write-up but I can't vouch for their quality).
Those sites dedicated to promoting the technique also include and reference other first person accounts. Most of these seem to be from people with a direct interest in advocating the approach, or, quotes where it's not clear how much direct experience there is, so they're worth treating skeptially, but they do suggest it's possible, with caveats. For example, TribalBaby.org" gives a first person E-book account of it working "part-time" in conjunction with (not instead of) "reduced reliance on" nappies. This fits the idea from above that it is possible, but isn't 100% reliable and does involved "accidents".
