Nop. The wireless networks have sufficient smarts in them to know when a call
is local or not. So you can always include the full phone number specification
, including the +.

(conventional landlines used to be quite dumb, and any call beginning with 1
was routed through their billing machines, and area codes only had 0 or 1 as
second digit, and local exchanges never had 0 or 1 as their middle digits).
However, this has changed in the last decade and phone switches have gotten
more intelligent now. However, on landlines, there is still the expectation
that you are not willing to pay long distance unless you add the 1.

On wireless, you trust the network to decide if your call is to be local or
long distance. Remember that cells do not necessarily match landline
boundaries. For instance, if you are in OKA, your cell phone may actually
connect to a Hudson tower across the lake, and calling the store in front of
you may be long distance because from Hudson to Oka it is long distance.

But from the same location, you can call montreal for free because a call to
montreal from hudosn is free, whereas from Oka, it is long distance (this may
have changed in the last decade, but it is just to demonstrate how cell phones
differ in local calling areas).

Also, Fido (at least when it began in Montreal back in 1997/1998) had all of
its montreal area coverage as local calls, which meant you could call from
St-jerome to the south-shore as a local call, but landline had to pay 35 cents
per minute.

Technically, the + symbol does NOT indicate a country code. The + is
used to indicate to dial the digits required to place an international
long distance call. For example, in Canada the digits are 011. The 1
in 1 AAA EEE NNNN is the country code for Canada and U.S.A.