We haven't yet heard of any problems with the RFID tags increasingly being used to monitor inmates in prisons, but it looks like the electronic tags used to keep watch on early release offenders are decidedly less reliable, at least according to a recent investigation into the matter in Scotland.
Amazon Watch said in its press release that the NGOs and their lawyers expect OAS to determine that the Brazilian government has violated the rights of Para residents impacted by the dam, and will recommend compensation.