Hi Bando,
I also have a 3 year old that was completely toilet trained, however he also went through a patch of wetting the bed & not lifting the seat up to the toilet, therefore wetting all the seat & floor to go with it! I too was sick of cleaning up the mess. I think the trick for the bed wetting is make sure they are warm, as acold sensation can trigger them, & also I took my son to the chiropractor ( as I go ) they say things like that can be because their backs are mis-aligned therefore putting unwanted pressure on things like their bladders etc. That worked for me ( whether it was a coincidence or what I dont know, but it did work) Good luck with it. My sister is a child health nurse & she has always told me that there are 2 places where are child can win the upper hand, the 1st being toilet training & the 2nd being eating! disgression is the best way to handle it.