When you book through RVezy, you are only charged the tax on the RVezy service fee, roadside, and the insurance deductible that you select. You will be asked to choose your place of residence and be charged the proper tax rate based on your location.
If you reside outside Canada, You will not be charged any tax for rentals in Canada.

If the owner has set up a tax account to collect his own taxes (HST or GST, etc..), you will be additionally charged the owners tax on his rental amount (nightly rate and any add-ons) based on his province of residence.
Note that you will not be double taxed on the rental as RVezy tax and the owner tax charge for separate items on the invoice.