Terrorism is not the only reason visas are being delayed or refused from many areas now. Immigration also is under orders to be strict because of the illegal immigrant problem.
Caribbean websites warned illegals in the US from their islands not to try to enter Canada for the Caribfest in Toronto. Not only would they just be turned back, but Canadian Immigration has turned some over to US Immigration and they face deportation.

The US has an unknown number of illegals from many countries, mostly Latin American and Caribbean (conservatively one million but probably double that) and some TV commentators are fanning opposition nightly (Robb report on CNN for one). Bush has suggested some sort of amnesty and job cards for those from Mexico, but this has stirred up more complaints (which may be what he intended).