done plenty, where needed.
it might look odd though... to my eye.
pegging through tells the story of the structure.
blind works when it follows the logic of the joinery.
it works structurally, so long as the pieces are large enough and you get good penetration beyond the tenon... (assuming that pegs can take the loads).
if it is a pool structure, without siding - what are you doing for a connection to the fnd or deck? does it have a roof? is the joinery you've planned OK for tension and compression (assuming a roof and an uplift wind load)?
