Well, I can't speak for Canada, but in most countries I've lived with the exception of the UK (non-dom rules) global income is taxed in your primary residence. So if your main economic activity is in Singapore and you declare your residence there so as to take advantage of its lenient tax rates (for example no capital gains tax), your Canadian home is not your primary tax residence and you should get hit by the land tax.

Conversely if you declare that you live in Canada whereas you're busy making a million a year in Dubai, that million ought to be taxed according to Canadian tax law as if you resided there.

There's plenty of rules already in existence to determine what is your primary tax residence as far as taxes are concerned, precisely to stop, say, a French resident from incorporating in Switzerland, getting paid into the structure, and not paying tax on his income (he can always try not to declare it, but then he becomes a criminal hoping that the rule of law is not thorough).