Can they do this way to avoid the cancellation of US PR

Dear Xiao BaiTu,

I am just wondering, since they have got Canadian citizenship,is it possible to proceed as the following to avoid US PR problem?

1)flying from China to Canada, such as Toronto. Then drive cars across the US border. so in this way, there will be no stamp on the visa.

2) Same way when going back to China.

Please advice

Thanks.