I've done everything from washing dishes, waiting tables, managing 2 coffee shops, landscape work, data entry, to my current work as a mobile developer. And I know where you're going with this, and no I've never had trouble finding work when I needed it.
You'd be right about the profile. But the thought of missed wages doesn't bother me because it was long ago, and if anything, they worked as hard, if not harder than I did. And we were friends doing the same shit work together.
That wouldn't cause me hard feelings, as a person who has worked both as a laborer and in the service industry.
If the level of my income is a function of how many other people are denied the ability to do the same job then I've got bigger concerns than my income level.
Research in the New Zealand context has shown that immigrants improve the economy. They generate a lot work for people helping them settle in and they often work hard themselves.