BE, I lurked on read some of your threads/contributions on EC earlier in the year and I've been reading the 'potty training' advice found in The Baby Whisperer books.
Having given it some thought I've been allowing DS to use a potty since he was about 8 months old (he's now 9 months) but I'm not specifically trying to potty train him (having taken your point that EC is communication, not potty training).
We have generally found this to be very positive and he already knows what the potty is for and can 'go' if he is sat on it. I'm not able to recognise his need to wee signals yet and he is not continent if he needs to go and is not offered the potty.
Anyway, my question is, what do you do if DC needs to use the toilet during a meal? DS needs to do a poo during at least one meal per day. Initially I took him down from the highchair and sat him on the potty but I found that (as well as being quite tricky and messy) he found this a bit annoying. I've stopped doing it as I only want him to have good potty associations.