The $2/$5 tight reg who check-raises the flop is not doing it as a bluff. At this level they're check-raising for protection or because they have a big hand. Either way you're usually not ahead.

Why they do it

$2/$5 regs who check-raise have usually thought about it before they do it. It's not a spazz move. They identified a threat to their hand or they flopped a monster. The check-raise bluff exists in their game but it's rare and usually on very specific board textures.

The adjustment

Give them credit unless the board texture makes a check-raise bluff logical (flush draw heavy, coordinated). With a one-pair hand just fold. Come back at them when you have it.

What it's worth

Calling a flop check-raise with top pair and folding the turn is a common and expensive mistake. Just fold the flop. Saves the turn and river money too - usually $80-150 total.