Physical currency trading.

I hope this is not too far off-topic here but here goes. I, like many, believe that the dollar is toast. I live within four hours of the Canadian border and obtaining CAD's is very easy to do here. Like many, I have spent the last few years diversifying what little assets I have into tangible things like physical PM's, real estate, etc. However, it feels like more diversification is in order.

I'm wondering if it would be wise to physically invest in CAD's for the long term? (10-20 years) I avoid safe deposit boxes except for storing documents but wonder if foreign currency in modest (10-50k) amounts would be safe from seizure should a bank holiday be declared? All input would be appreciated.

I_S