To turn off the roaming prompts, have you tried turning off data roaming and manually selecting Rogers as your phone's network instead of letting it auto select a preferred network which will likely be whatever is the strongest signal it finds, which is obviously going to be a problem near the border?  
Also, have you done your due diligence on which carrier has the best coverage/signal around your house.  You can google up a map of where each carrier's cell towers are.  I see way more Telus towers around Ocean Park vs Rogers.  If you are finding you are getting dead zones of coverage after config'ing your settings specifically for Rogers, you should continue to report it as it's a coverage gap instead of your phone getting confused as to what network it should latch onto or change to a carrier that has a tower closer to your home.