I would suggest, if using small legos, that you glue the pieces together so you don't have to worry about getting them bumped over. (A toxic free glue) I think the chance of it being eaten is too great unless you are prepared to do some major vet bills to retrieve the pieces.
Of course you may not be able to reuse the pieces later so I would recommend investing in legos that belong to you and not your little brother.
You can get quite creative with lego...imagine what the viv's would look like with USS Enterprise 'ANCHORED' to the side (did you note the 'safety' word). You don't want pieces toppling over and squishing poor Gismo.
If someone actually does this, do you think you could post a pic.